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(BQ) Part 1 book Diagnostic imaging gastrointestinal presents the following contents: Abdominal manifestations of systemic conditions; peritoneum, mesentery and abdominal wall; esophagus; stomach; duodenum, small intestine; colon.
ii Michael P Federle, MD Professor and Associate Chair for Education Department of Radiology Stanford University Medical Center Stanford, California Siva P Raman, MD Assistant Professor of Radiology Johns Hopkins University School of Medicine Baltimore, Maryland iii 1600 John F Kennedy Blvd Ste 1800 Philadelphia, PA 19103-2899 DIAGNOSTIC IMAGING: GASTROINTESTINAL, THIRD EDITION ISBN: 978-0-323-37755-3 Copyright © 2015 by Elsevier All rights reserved No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein) Notices Knowledge and best practice in this field are constantly changing As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility With respect to any drug or pharmaceutical products identified, readers are advised to check the most current information provided (i) on procedures featured or (ii) by the manufacturer of each product to be administered, to verify the recommended dose or formula, the method and duration of administration, and contraindications It is the responsibility of practitioners, relying on their own experience and knowledge of their patients, to make diagnoses, to determine dosages and the best treatment for each individual patient, and to take all appropriate safety precautions To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein Publisher Cataloging-in-Publication Data Diagnostic imaging Gastrointestinal / [edited by] Michael P Federle and Siva P Raman 3rd edition pages ; cm Gastrointestinal Includes bibliographical references and index ISBN 978-0-323-37755-3 (hardback) Digestive organs Imaging Handbooks, manuals, etc Diagnostic imaging I Federle, Michael P II Raman, Siva P III Title: Gastrointestinal [DNLM: Radiography, Abdominal methods. Handbooks Digestive System Diseases radiography Handbooks Diagnostic Imaging Handbooks WI 900] RC944.D526 2015 617.5/507543 dc23 International Standard Book Number: 978-0-323-37755-3 Cover Designer: Tom M Olson, BA Cover Art: Lane R Bennion, MS Printed in Canada by Friesens, Altona, Manitoba, Canada Last digit is the print number: iv Dedications This book is dedicated to the phenomenal referring physicians at Stanford and Johns Hopkins Medical Centers who attract and care for some of the most challenging and LQWHUHVWLQJSDWLHQWVRIWHQUHIHUUHGVSHFLƬFDOO\WRWKHP because of their well-earned reputations for excellence They keep us “on our toes,” and the most rewarding part of our jobs is to participate with them in advancing the evaluation and care of patients with abdominal disease and disorders MPF To my loving wife, Janani Venkateswaran, for her boundless understanding and patience To my parents, Raghu and Visali, for their support throughout my entire career and education To all my colleagues at Johns Hopkins SPR v vi Contributing Authors Amir A Borhani, MD Assistant Professor of Radiology University of Pittsburgh School of Medicine Pittsburgh, Pennsylvania Mitchell Tublin, MD Professor and Vice Chairman Chief of Abdominal Imaging Department of Radiology University of Pittsburgh School of Medicine Pittsburgh, Pennsylvania 5%URRNH-HƪUH\0' Professor and Vice Chairman Department of Radiology Stanford University School of Medicine Stanford, California vii Preface The second edition of Diagnostic Imaging: Abdomen was a major expansion of the ƬUVWHGLWLRQFRQWDLQLQJRYHUDGGLWLRQDO diagnoses In planning this, the third edition, we soon realized that comprehensive coverage of all of the advances in imaging and management of abdominal disorders was no longer possible in a single volume text Therefore, we elected to separate diagnoses judged primarily “gastrointestinal,” covered in this thoroughly updated text, from the “genitourinary” topics, to be covered in a subsequent book We have maintained the classic Amirsys style of bulleted text, allowing us to present factual material in less than half the space with greater clarity and readability We have, however, also maintained and expanded the popular Introduction and Overview sections, which are written in a more informal prose style, to help readers grasp the essential anatomical issues, imaging protocols, and general approaches to the most common DQGLPSRUWDQWGLVRUGHUVDƪHFWLQJWKDWRUJDQ system As a new feature, we have added lists of WKHPRVWLPSRUWDQWGLƪHUHQWLDOGLDJQRVHV to each Introduction and Overview section, helping readers to zero in, for instance, on the possible etiologies for a “cystic SDQFUHDWLFPDVVq5HIHUHQFHWRVSHFLƬF chapters on the most likely candidates will then quickly lead to a more accurate and VSHFLƬFGLDJQRVLV viii Fluoroscopy in the modern era (read, CT, and endoscopy) has evolved to focus primarily on pre- and postoperative evaluation of patients for surgical alterations of the GI tract Therefore, we have de-emphasized the more HVRWHULFDVSHFWVRIƮXRURVFRSLFGLDJQRVLVRI diseases in favor of more expansive coverage of the radiologist’s role in evaluating patients IRUEDULDWULFVXUJHU\DQWLUHƮX[SURFHGXUHV esophageal and bowel resections, and so forth Additional detailed diagnostic material, images, and references are included in Elsevier’s Expert Consult, an eBook that accompanies the print version of Diagnostic Imaging: Gastrointestinal, Third Edition We have updated and replaced most images from the second edition, maintaining only those judged to be so classic that newer examples would not be an improvement All references and text have been updated as well, with all material being current to within a few months of the publication date of this book The rapid preparation of this book was made possible in part by limiting the primary authorship to two experienced and highly motivated authors, who took responsibility for ZULWLQJDQGLOOXVWUDWLQJDOOSOXVFKDSWHUV We hope that this new edition of Diagnostic Imaging: Gastrointestinal will be a welcome addition to your library, but only after you have read it! Michael P Federle, MD Professor and Associate Chair for Education Department of Radiology Stanford University Medical Center Stanford, California Siva P Raman, MD Assistant Professor of Radiology Johns Hopkins University School of Medicine Baltimore, Maryland ix Colon Colon Carcinoma (Left) Upright chest radiograph of an 82-year-old woman who complained of distention and sudden abdominal pain shows free intraperitoneal gas and a distended colon (Right) Coronal-reformatted CT section in the same case shows stool and gas distending the colon st Ascites and free air were also evident A distal colon cancer is one of the most common causes for colonic obstruction in older adults (Left) Axial CT section in the same case shows an "apple core" obstructing lesion ſt of the sigmoid colon Note the short segment, soft tissue density of the wall thickening and luminal narrowing (Right) More caudal CT section in the same case shows extraluminal gas st and ascites , indicating perforation of the colon (Left) CT of a 66-year-old man who had prior resection of a sigmoid colon cancer and now presents with flank pain and weight loss shows a descending colostomy and extensive retroperitoneal lymphadenopathy st that enveloped the left ureter and caused hydronephrosis (not shown) (Right) Axial PET/CT in the same case shows large FDG-avid masses st that envelop and obstruct the left ureter, representing recurrent colon carcinoma In cases of suspected recurrence of CRC, PET/CT is the optimal test 528 Colon Carcinoma Colon (Left) Axial CT section of a 31year-old man presenting with constipation and bright red blood per rectum shows gross dilation of the colon (Right) CECT in the same case shows asymmetric, soft tissue density thickening of the wall of the descending colon ſt (Left) Adjacent CECT section in the same case shows an "apple core" lesion ſt at the junction of the descending and sigmoid colon (Right) Coronalreformatted CT in the same case shows gross distention of the colon with stool and gas (Left) Another coronal CT section shows the abrupt narrowing of the colon by the "apple core" lesion ſt Note the abrupt and short thickening of the colonic wall and narrowing of the lumen The clinical and imaging features are typical of a distal colon cancer, though the patient is younger than most affected patients (Right) In order to overcome the nearcomplete luminal obstruction and to clean the colon prior to surgical resection, a metallic stent was deployed across the obstructing tumor under endoscopic guidance 529 Colon Rectal Carcinoma KEY FACTS IMAGING • PET/CT: Excellent for staging and recurrence • CT, MR: Asymmetric mural thickening ± irregular surface ○ Extracolonic tumor extension: Irregular external (serosal) margin of rectum ○ Strands of soft tissue extending from serosal surface into perirectal fat ○ Loss of tissue fat planes between rectum and surrounding muscles and organs ○ Metastasis to lymph nodes at external iliac and paraaortic chain, inguinal, retroperitoneum, or porta hepatis • Mass; pericolonic infiltration, lymphadenopathy may be shown better on MR than CT • Transrectal ultrasonography: Best for local invasion, pelvic nodes • May have lung and bone metastases before liver metastases (unlike typical pattern for colon carcinoma) ○ Due to dual venous drainage, including internal iliac and hemorrhoidal veins TOP DIFFERENTIAL DIAGNOSES (Left) Axial CECT in a 68-yearold man with frequent passage of small amounts of mucus and stool shows a large rectal mass ſt that breaks through the rectal wall st, interrupting the otherwise complete rectal mucosal enhancement There was no colonic obstruction, suggesting the soft nature of this villous carcinoma (Right) CT in the same patient shows extensive infiltration of the perirectal fat planes , strongly suggesting transmural spread of tumor and the need for neoadjuvant therapy prior to resection (Left) Transrectal ultrasonography shows a bulky rectal mass ſt with invasion through the submucosa in this patient with T3 stage rectal carcinoma (Right) Axial CECT shows extensive pulmonary metastases from rectal carcinoma in a patient with no liver metastases The dual venous drainage of the rectum (systemic and portal) explains this pattern and results in very different clinical behavior of rectal and colon cancers 530 • Invasion by adjacent tumor (cervix, prostate, bladder) • Rectal villous adenoma • Trauma or infection PATHOLOGY • Adenocarcinoma: Arises from mucin-producing glands (80% of rectal tumors) • Squamous cell (cloacogenic) carcinoma (20% of rectal tumors) DIAGNOSTIC CHECKLIST • Image detection of perirectal tumor spread is vital; requires preoperative radiation ± chemotherapy Rectal Carcinoma Definitions • Malignant transformation of rectal mucosa IMAGING General Features • Best diagnostic clue ○ Polypoid rectal mass with irregular surface • Morphology ○ Early cancer: Sessile or pedunculated tumors ○ Advanced cancer: Annular, semiannular, polypoid or "carpet" tumors ○ Most common in rectum: Sessile and polypoid • Other general features ○ Radiologic and histologic features are similar to colon carcinoma Radiographic Findings • Fluoroscopic-guided barium enema ○ Early cancer: Sessile (plaque-like) lesion – Flat, protruding lesion with broad base and little elevation of mucosa (profile view) ○ Advanced cancer: Polypoid lesion – Dependent wall: Filling defect in barium pool – Nondependent wall: Etched in white ○ Advanced cancer: Semiannular ("saddle") lesion – Transition to annular carcinoma ("apple core") – Convex barium-etched margins (profile view) CT Findings • Mass and focal or circumferential wall thickening • Asymmetric mural thickening (> mm) ± irregular surface • Extracolonic tumor extension ○ Mass with irregular external (serosal) border ○ Strands of soft tissue extending from serosal surface into perirectal fat ○ Loss of tissue fat planes between rectum and surrounding muscles and organs • Metastasis to lymph nodes at external iliac and paraaortic chain, inguinal, retroperitoneum, or porta hepatis • May have lung and bone metastases before liver metastases ○ Due to dual venous drainage, including internal iliacs MR Findings • Mass; pericolonic infiltration, lymphadenopathy slightly better than on CT ○ Same tumor morphology as on CT ○ Tumor is dark on T1WI, bright on T2WI and DWI • Endorectal coil: Improves resolution but may not be worth effort Ultrasonographic Findings • Transrectal ultrasonography ○ Best means of determining depth of wall invasion and pelvic lymphadenopathy ○ Focal or circumferential wall thickening ○ Hypoechoic mass with disruption of wall layers ○ Metastases to lymph nodes: Spherical, hypoechoic, and distinct margins Colon ○ Rings of different echogenicities (center → outer) – Innermost ring: Hyperechoic; interface between balloon and mucosa – 2nd ring: Hypoechoic; muscularis mucosae – 3rd ring: Hyperechoic; submucosa – 4th ring: Hypoechoic; muscularis propria – 5th ring: Hyperechoic; perirectal fat or serosa ○ Sonographic staging based on TNM classification – T1: Confined to mucosa/submucosa; middle echogenic layer intact – T2: Confined to rectal wall; outermost echogenic layer is intact – T3: Penetrates into perirectal fat; disrupting outer hyperechoic ring TERMINOLOGY Nuclear Medicine Findings • PET/CT ○ Combines morphologic information (of CT) with metabolic information (of PET) ○ Excellent for staging and detection of recurrence ○ Fluorine 18-labeled deoxyglucose uptake is 2x higher in tumors than normal or nonmalignant lesions Imaging Recommendations • Best imaging tool ○ Detection: Barium enema or CT colonography ○ Staging: CECT or MR plus transrectal ultrasonography (wall invasion and nodes) ○ Tumor recurrence, surveillance: PET/CT DIFFERENTIAL DIAGNOSIS Invasion by Adjacent Tumor • • • • Carcinoma of cervix Prostate carcinoma Bladder carcinoma Can be hard to differentiate from primary rectal tumor Rectal Villous Adenoma • Polypoid lesion with granular, reticular, or "cauliflower" appearance • High risk of malignant degeneration • Similar to "carpet" lesion in advanced rectal cancer Trauma • Penetrating injuries: Anal intercourse and insertion of foreign bodies • Fibrosis and stricture (chronic) can simulate cancer Infection • Mucosal ulceration or granular mucosal pattern • Mechanism: Anal sex, spread from vaginal discharge, or lymphatic extension from inguinal lymph nodes • Most common: Chlamydia trachomatis → lymphatic tissue infection → lymphogranuloma venereum (LGV) • Other STDs include Neisseria gonorrhoeae, HSV, and syphilis • May progress to fistula, perirectal abscess, or stricture (chronic) PATHOLOGY General Features • Etiology 531 Colon Rectal Carcinoma • • • • • ○ Adenocarcinoma – ↓ fiber + ↑ fat and animal protein diet – History of colorectal adenoma or carcinoma – Family history and inflammatory bowel disease ○ Squamous cell carcinoma – HIV-positive homosexual males – Human papillomavirus (HPV) types 16, 18, 45, 46 – Lubricants, cleansers, and mechanical irritation ○ Pathogenesis – Adenocarcinoma: Adenoma-carcinoma sequence – Squamous cell carcinoma: Squamous metaplasia → dysplasia → carcinoma Genetics ○ Adenocarcinoma: Mutation in proto-oncogene, tumor suppressor genes, or DNA mismatch repair genes Colon cancers: Rectum accounts for 20% and rectosigmoid 15% Rectal cancer tends to invade locally (lacks serosa) Metastases: From upper 2/3 of rectum ○ Portal system → liver ○ Batson vertebral venous plexus → lumbar and thoracic vertebra, periaortic nodes Metastases: From lower 1/3 of rectum ○ Superior hemorrhoidal vein → portal → liver ○ Middle hemorrhoidal vein → IVC → lung Staging, Grading, & Classification • Surgical-pathologic (modified Dukes) staging of colon cancer with TNM correlation ○ Stage A (T1N0M0): Limited to mucosa ± submucosa ○ Stage B (T2 or and N0M0): Limited to or invades adjacent tissues ○ Stage C (T2 or and N1M0): Lymph node metastases ○ Stage D (any T and N, M1): Distant metastases ○ Sigmoidoscopy with mucosal biopsy Demographics • Age ○ Adenocarcinoma: Age > 50 years, peak at 70 years • Gender ○ M:F = 3:2 • Epidemiology ○ Adenocarcinoma: More common in North America, Europe, and New Zealand Natural History & Prognosis • Complications ○ Hemorrhage, obstruction, perforation, and fistula • Prognosis ○ Overall 5-year survival (50%) – Dukes stage A (81-85%) – Dukes stage B (64-78%) – Dukes stage C (27-33%) – Dukes stage D (5-14%) Treatment • Surgical resection (depends on location) and removal of lymphatic drainage vessels ± adjuvant chemotherapy • Pre- and postoperative radiation ± chemotherapy therapy (for locally advanced tumor) • Follow-up ○ CT: 3-4 months after surgery, then every months for 23 years, then annually for years ○ CEA titer: If elevated, CT is indicated (PET/CT best) DIAGNOSTIC CHECKLIST Consider • Evaluate entire colon for synchronous lesions Gross Pathologic & Surgical Features Image Interpretation Pearls • Flat, infiltrative, annular or ulcerative, and rolled borders • Annular constriction or "napkin-ring" appearance → obstruction, ulceration, and intramural spread • Squamous cell carcinoma: Mass from epithelium of anorectal junction (dentate line) • Image detection of perirectal tumor spread is vital; requires preoperative radiation ± chemotherapy SELECTED REFERENCES Microscopic Features • Adenocarcinoma: Arises from mucin-producing glands (80% of rectal tumors) • Squamous cell (cloacogenic) carcinoma (20% of rectal tumors) ○ Mixture of basaloid cell, transitional cell with squamous differentiation, adenoid cyst, and mucoepithelial cell CLINICAL ISSUES Presentation • Most common signs/symptoms ○ Hematochezia, rectal pain, change in bowel habits ○ Perineal or sacral pain (chronic) ○ Squamous cell carcinoma – Anal pain, anal discharge, and tenesmus • Lab data ○ HIV (PCR) test may be positive ○ Carcinoembryonic antigen (CEA) > 2.5 μg/L • Diagnosis 532 Lim SB et al: Nonoperative strategies for rectal cancer following a complete clinical response to preoperative chemoradiation: a few considerations Oncology (Williston Park) 28(7):620-1, 2014 Minsky BD et al: MRI-based treatment decision making for rectal cancer Oncology (Williston Park) 28(8):680-1, 2014 Monson JR et al: Failure of evidence-based cancer care in the United States: the association between rectal cancer treatment, cancer center volume, and geography Ann Surg 260(4):625-31; discussion 631-2, 2014 Winter D: Outcomes in locally advanced rectal cancer with highly selective preoperative chemoradiotherapy editor's comments Br J Surg 101(10):1298, 2014 Hoffman JR et al: Carcinoma of the prostate with aggressive rectal invasion Am Surg 75(5):434-6, 2009 Platell C: Transanal endoscopic microsurgery ANZ J Surg 79(4):275-80, 2009 Shen SS et al: Number of lymph nodes examined and associated clinicopathologic factors in colorectal carcinoma Arch Pathol Lab Med 133(5):781-6, 2009 Rectal Carcinoma Colon (Left) Axial PET/CT in a 54year-old man with AIDS shows an FDG-avid mass ſt in the anal canal, representing a primary anorectal carcinoma (Right) Axial PET/CT in the same patient shows similar FDG-avid masses in lymph node metastases st in the porta hepatis This patient had no liver metastases, again emphasizing the unique patterns of spread in rectal vs colon cancer Anal cancer is relatively common in homosexual men with AIDS and is related to papilloma viral infection (Left) Axial T1WI MR in a 58year-old woman with prior low anterior resection of a rectal carcinoma, now returning with right leg sciatica, shows a large irregular mass ſt that extends into the right sciatic notch st and posterior wall of the bladder (Right) Axial T2WI MR in the same patient shows the recurrent rectal cancer ſt and its invasion of the bladder and pelvic side wall muscles st (Left) Axial CECT in a young woman who underwent colectomy for granulomatous colitis shows a circumferential mass ſt within the rectum that represents carcinoma Note the adenopathy adjacent to the rectum and the tumor in the sciatic foramen st (Right) Axial PET/CT in the same patient shows an FDG-avid tumor in the rectum ſt and in the sciatic foramen st The bladder is filled with urine containing excreted FDG 533 Colon Familial Polyposis and Gardner Syndrome KEY FACTS TERMINOLOGY • Autosomal dominant genetic disorder characterized by formation of innumerable colonic adenomatous polyps at young age and increased risk for colonic and extracolonic tumors IMAGING • Innumerable colonic filling defects or ring shadows ± extraintestinal lesions • Adenomatous (± malignant) polyps in ○ Colon > stomach > duodenum > small bowel • varied expressions of familial adenomatous polyposis (FAP) ○ FAP coli and Gardner syndrome • Small (80% < mm) and usually sessile ○ May be widely scattered radiolucent filling defects ○ Polyps may carpet colon • Imaging tests: Double-contrast barium studies of colon and upper GI tract (Left) Graphic shows innumerable small polyps and multifocal carcinomas ſt representative of the colonic lesion types seen in patients with familial polyposis coli (Right) Spot film from an aircontrast barium enema demonstrates multiple small radiolucent filling defects , which represent sessile adenomatous polyps along the sigmoid colonic mucosa (Left) Spot film from an aircontrast barium enema shows innumerable small polyps in the sigmoid colon (Right) Gross pathology of a resected colon shows adenomatous polyps carpeting the colon surface Note the pedunculated appearance of some polyps While these adenomas generally start as sessile lesions, they may be drawn out onto stalks due to the peristaltic force of the bowel 534 ○ CT or MR (for abdominal tumors) TOP DIFFERENTIAL DIAGNOSES • • • • • Retained feces and food Lymphoid hyperplasia Metastases and lymphoma Pseudopolyps Primary pneumatosis coli PATHOLOGY • Autosomal dominant trait (2/3 of cases) with high penetrance • Spontaneous mutations (1/3 of cases) CLINICAL ISSUES • Mean age at diagnosis = 16 years; 95% have polyps by 35 years • Colon carcinoma by 34-43 years of age Familial Polyposis and Gardner Syndrome Abbreviations • Familial adenomatous polyposis (FAP) syndrome • Gardner syndrome may have the same genetic mutation ○ Distinction from FAP is largely semantic Definitions • Autosomal dominant genetic disorder characterized by formation of innumerable colonic adenomatous polyps at young age and by increased risk for colonic and extracolonic tumors IMAGING General Features • Best diagnostic clue ○ Innumerable colonic filling defects or ring shadows on barium enema • Location ○ Adenomatous polyps in – Colon > stomach > duodenum > small bowel • Size ○ Varies from pinpoint to > cm • Morphology ○ Sessile or pedunculated polypoid lesions • Other general features ○ FAP: Rare, but it is the most common polyposis syndrome ○ varied expressions of FAP: FAP coli and Gardner syndrome – Gardner syndrome □ Familial polyposis coli, osteomas, epidermoid (sebaceous) cysts □ Soft tissue tumors: Desmoid, mesenteric fibromatosis, lipoma □ Dental abnormalities; periampullary, duodenal, and thyroid carcinomas ○ Hundreds or thousands of polyps may carpet colon ○ FAP adenomas: Small (80% < mm) and usually sessile ○ Extracolonic GI tract manifestations of FAP – Stomach □ Fundic gland polyps and adenomas in > 50% of cases – Duodenum: Adenomas of 2nd part, and periampullary in > 50% of cases □ Periampullary cancer: 2nd most frequent site of cancer outside colon, seen in 12% of FAP patients – Jejunum and ileum □ Adenomas, lymphoid hyperplasia in > 20% of cases ○ Associated with ↑ incidence of malignant CNS tumors Radiographic Findings • Fluoroscopic-guided double contrast barium enema ○ Innumerable variably sized radiolucent filling defects ○ Carpet entire colon, especially rectosigmoid ○ May be widely scattered radiolucent filling defects • Double-contrast upper GI, small bowel ○ Multiple small filling defects (polyps) in stomach, duodenum, jejunum, and ileum CT Findings • CECT ○ Useful for diagnosing and staging colon carcinomas – Colorectal cancers are often multiple – Look for nodal, peritoneal, hepatic metastases ○ Both desmoid and mesenteric fibromatosis: Higher attenuation than muscle • CT colonography can detect polyps but uncertain role in this setting (FAP) Colon TERMINOLOGY Imaging Recommendations • Best imaging tool ○ Double-contrast barium studies of colon and upper GI tract • CT or MR (for abdominal tumors) DIFFERENTIAL DIAGNOSIS Retained Feces and Food • Filling defects in barium pool, mimicking polyps Lymphoid Hyperplasia • Lymphoid follicles ○ Aggregates of lymphocytes in muscularis mucosae ○ Seen in 50% of barium studies for children, 13% for adults – Usually more prominent in right colon and distal small bowel • Barium studies ○ Innumerable small or tiny radiolucent nodules • Distinguished by clinical history and ill-defined borders of lymphoid follicle (submucosal) Metastases and Lymphoma • Rarely as numerous as lesions in FAP • Metastases (e.g., malignant melanoma, breast, lung) ○ Smooth polypoid submucosal lesions of different sizes seen as filling defects that may mimic polyps • Lymphoma ○ Distribution: Stomach (51%), small bowel (33%), colon (16%), esophagus (< 1%) ○ Low-grade MALT lymphoma – Seen only in stomach due to Helicobacter pylori gastritis – Confluent nodules of varying size (filling defects) – May be indistinguishable from gastric polyps ○ Non-Hodgkin lymphoma – Small or bulky polypoid masses may mimic polyps – Smooth surface, broad base, sessile lesions ± central depressions or ulcerations – Bull's-eye sign: Polypoid mass with ulceration – Markedly thickened bowel wall and folds – Regional or widespread adenopathy seen Pseudopolyps • Examples: Ulcerative colitis (common), granulomatous colitis • types of pseudopolyps ○ Inflammatory pseudopolyps ○ Postinflammatory pseudopolyps • Inflammatory pseudopolyps 535 Colon Familial Polyposis and Gardner Syndrome ○ Islands of elevated, inflamed, edematous mucosa surrounded by ulceration appear as pseudopolyps – Represent remnants of preexisting mucosa and submucosa rather than new growths ○ Natural progression of "collar-button" ulcers, which extend, interconnect, and mimic pseudopolyps • Postinflammatory pseudopolyps (mucosal overgrowth) ○ Regenerated mucosa results in polypoid lesions – Long and filiform or bush-like structure simulating villous adenoma; may be small and rounded ○ Seen during healing = postinflammatory pseudopolyps Primary Pneumatosis Coli • Cystic intramural collections of gas in colon • Asymptomatic • Not due to ischemia PATHOLOGY General Features • Etiology ○ FAP is inherited as autosomal dominant trait (2/3 of cases) ○ Occasionally due to spontaneous mutations (1/3 of cases) ○ High penetrance (affected patients will develop signs and symptoms) • Genetics ○ Truncating germline mutations of APC gene located on chromosome 5q • Associated abnormalities ○ Extracolonic malignancies associated with FAP – Duodenal ampullary carcinoma (12% lifetime risk) – Thyroid cancer – Childhood hepatoblastoma – Gastric carcinoma – CNS tumors (mostly medulloblastoma) ○ Extraintestinal manifestations: Gardner syndrome – Epidermoid cyst, lipoma, fibroma, desmoid tumors (329%), mesenteric fibromatosis, peritoneal adhesions, retroperitoneal fibrosis – Osteomas: Membranous bone (50%), mandible (80%) – Teeth: Odontoma, unerupted supernumerary teeth – Thyroid cancer: Papillary type more common in girls and young women CLINICAL ISSUES Presentation • Most common signs/symptoms ○ Rectal bleeding and diarrhea (75% of cases) ○ Asymptomatic, pain, mucus discharge ○ Family history of colonic polyps (66-80% of cases) Demographics • Age ○ Mean at diagnosis = 16 years; 95% have polyps by 35 years • Gender ○ M=F • Epidemiology ○ FAP affects in 10,000-30,000 people in USA ○ Accounts for > 1% of colon cancers in USA Natural History & Prognosis • Complications ○ Polyps: Malignant transformation – Colon > periampullary > stomach > jejunum ○ Colon carcinoma by 34-43 years of age – Almost all affected individuals will develop colon cancer unless they have prophylactic colectomy • Prognosis ○ Poor if abdominal desmoids, colonic carcinoma, or ampullary carcinoma develop Treatment • Prophylactic total colectomy at ~ 20 years of age • Permanent ileostomy, Kock pouch • Continent endorectal pull-through pouch DIAGNOSTIC CHECKLIST Consider • Check for family history: Colonic polyps, abdominal soft tissue tumors, and malignancies at young age Image Interpretation Pearls • Gardner syndrome: Soft tissue tumors, bony osteomas, dental defects, and periampullary cancer SELECTED REFERENCES Gross Pathologic & Surgical Features • Innumerable polyps carpeting colonic mucosa • Desmoid tumor ○ Confined to muscle, fascia, or deeply infiltrative ○ Size: 5-20 cm; firm and gritty texture; lack capsule ○ Cut surface: Glistening white + trabeculated Microscopic Features • Adenomas ○ Tubular, tubulovillous, and villous; ± atypia or mitosis – No difference from sporadic type of colonic polyps • Desmoid tumor ○ Spindle-shaped cells and dense bands of collagen 536 Vitellaro M et al: Risk of desmoid tumours after open and laparoscopic colectomy in patients with familial adenomatous polyposis Br J Surg 101(5):558-65, 2014 Wood LD et al: Upper GI tract lesions in familial adenomatous polyposis (FAP): enrichment of pyloric gland adenomas and other gastric and duodenal neoplasms Am J Surg Pathol 38(3):389-93, 2014 Zhang Y et al: Adenomatous polyposis coli determines sensitivity to the EGFR tyrosine kinase inhibitor gefitinib in colorectal cancer cells Oncol Rep 31(4):1811-7, 2014 De Rosa M et al: Implication of adenomatous polyposis coli and MUTYH mutations in familial colorectal polyposis Dis Colon Rectum 52(2):268-74, 2009 Herráiz M et al: Recognition and management of hereditary colorectal cancer syndromes Rev Esp Enferm Dig 101(2):125-32, 2009 Mavrogiannis LA et al: Novel human pathological mutations Gene symbol: APC Disease: familial adenomatous polyposis Hum Genet 125(3):333, 2009 Spigelman AD: Extracolonic polyposis in familial adenomatous polyposis: so near and yet so far Gut 53(3):322, 2004 Macari M et al: Diagnosis of familial adenomatous polyposis using twodimensional and three-dimensional CT colonography AJR Am J Roentgenol 173(1):249-50, 1999 Familial Polyposis and Gardner Syndrome Colon (Left) Spot film from an aircontrast barium enema shows innumerable small polyps, most within the range of 2-5 mm Colonic polyps in familial polyposis can range in number from dozens to thousands, as in this case (Right) Axial CECT in a 26-year-old man, unaware of the history of colon cancer in his family, shows numerous hepatic metastases from colon carcinoma (Left) Axial CECT in the same patient shows of colonic masses ſt, all of which represent advanced colon cancer with invasion through the wall, regional lymphadenopathy, and hepatic metastases (Right) Axial CECT in the same patient shows a large rectal mass ſt with extension through the wall, infiltration of the perirectal fat, and metastases to regional nodes The patient had presented with rectal bleeding and weight loss (Left) Upper GI series spot film shows the stomach carpeted with small polyps, all fairly small and uniform in size While these resemble hyperplastic polyps radiographically, this patient has familial polyposis with adenomatous polyps that have potential for malignant degeneration (Right) Upper GI series spot film in a patient with familial polyposis and Gardner syndrome shows several adenomatous polyps in the duodenum ſt 537 Colon Familial Polyposis and Gardner Syndrome (Left) This 37-year-old man had minimal contact with physicians and presented with rectal bleeding and weight loss CT shows multiple liver metastases (Right) CT in the same case shows multiple liver metastases and a small mass at the duodenal ampulla ſt, subsequently proven to be an adenoma (Left) CT in the same case shows a small bowel intussusception st, likely induced by small bowel polyps (not visualized) (Right) CT in the same case shows a mass in the buttocks that is higher in attenuation than adjacent muscle and likely represents a desmoid tumor or fibromatosis (Left) CT in the same case shows a mass ſt in the sigmoid colon, subsequently proved to be an adenocarcinoma (Right) Following the abdominal CT in this patient, a CT section through the facial bones reveals cortical thickening and osteomas st All of the highlighted findings are typical features of Gardner syndrome 538 Familial Polyposis and Gardner Syndrome Colon (Left) This 19-year-old woman had known FAP and had a total colectomy She later presented with a hard, palpable abdominal mass Axial CECT images show evidence of the prior colectomy with an ileal pouch There is a large mass ſt in the right rectus muscle that proved to be a desmoid tumor within an incision site (Right) Axial CT in the same case shows a more subtle mass st at the base of the mesentery, also proven to represent desmoid or aggressive fibromatosis (Left) This young woman, presenting with weight loss and anemia, had no family history of colon cancer CT shows multiple liver metastases (Right) CT in the same case shows a mass ſt within the ascending colon, subsequently proven to represent colon cancer (Left) Another CT section in this case shows a tumor in the recto-sigmoid colon , and extensive spread to the regional nodes st (Right) CT in the same case shows the rectal cancer with extensive infiltration into the perirectal tissues As with this patient, some cases of FAP lack a family history and may result from spontaneous genetic mutation 539 Colon Appendiceal Tumors KEY FACTS TERMINOLOGY • Primary malignant neoplasm of appendix ○ Mucinous cystadenocarcinoma (90%) ○ Colonic-type adenocarcinoma (10%) ○ Lymphoma (< 1%) ○ Carcinoid (common, usually incidental at appendectomy) IMAGING • Round or oval, cystic or solid, mass near tip of cecum • Mucocele ○ RLQ soft tissue mass with curvilinear mural calcification on radiography is highly suggestive ○ Ovoid cystic mass ± internal echoes (septations) on US • Mucinous tumor: RLQ cystic mass, usually > cm ○ Mucinous type has strong propensity to form mucocele ○ May have curvilinear calcification in wall ○ Mucinous cystadenocarcinoma is most common cause of pseudomyxoma peritonei • Lymphoma: Cylindrical, soft tissue density mass (Left) Axial CECT shows an oval, well-encapsulated, cystic mass ſt arising from the tip of the cecum in this 62-year-old man with mucinous carcinoma of the appendix With imaging alone, a benign mucocele may not be distinguished from a mucinous carcinoma (Right) Axial CECT in an 80-year-old man with pseudomyxoma peritonei due to ruptured mucinous carcinoma of the appendix shows the classic scalloped appearance of the surface of the liver due to peritoneal gelatinous metastases (Left) Axial CECT in a 60-yearold woman with chronic RLQ pain shows a hypodense mass with a typical appearance of liver metastasis (Right) Axial CT in the same case shows a thick-walled appendix ſt with a calcified appendicolith st within its lumen and infiltration of adjacent fat While these findings mimic those of appendicitis, there is much more soft tissue density within the wall than would be expected with simple appendicitis Liver metastases suggest the correct diagnosis of appendiceal carcinoma 540 ○ Cannot distinguish from carcinoma on CT • Carcinoid ○ Rarely diagnosed clinically or by imaging prior to appendectomy TOP DIFFERENTIAL DIAGNOSES • Mucocele of appendix (other etiologies) ○ Nonneoplastic forms rarely exceed cm in diameter • Appendicitis (abscess) ○ More inflammatory changes are seen ○ No liver or peritoneal metastases • Ovarian cystic mass ○ Identify right ovary as source or separate from mass CLINICAL ISSUES • Appendiceal tumors are found in 1% of appendectomies (usually carcinoid) • Appendiceal tumors constitute 0.5% of intestinal neoplasms Colonic Metastases and Lymphoma IMAGING • Best imaging tools: CT, MR, barium enema • Protocol advice ○ Intravenous contrast for CT or MR ○ Double contrast barium enema TOP DIFFERENTIAL DIAGNOSES • Adenocarcinoma ○ Short, focal, "apple core" lesion < 10 cm in length ○ More likely to cause colonic obstruction than submucosal lymphoma or mets • Colonic Kaposi sarcoma • Ileocolic tuberculosis • Gastrointestinal stromal tumor PATHOLOGY • Metastatic spread from melanoma or primary tumor of stomach, lung, or breast (rarely, other cancers) ○ Gastric cancer may directly invade transverse colon along gastrocolic ligament • Lymphoma may arise from and be limited to colon Colon KEY FACTS CLINICAL ISSUES • Most common signs/symptoms: Rectal bleeding, symptoms of obstruction, especially if intussusception is present • 50% 5-year survival rate for patients with primary colonic lymphoma • Prognosis is poor for patients with metastases to colon from melanoma, breast, lung, or gastric cancer DIAGNOSTIC CHECKLIST • Consider lymphoma for bulky mass with aneurysmal dilatation of lumen and no colonic obstruction • "Serrated" edge of transverse colon (on barium enema) may indicate gastric cancer invading gastrocolic ligament (Left) Axial CECT in a 67-yearold man presenting with months of intermittent rectal bleeding and clinical symptoms of obstipation shows a bulky enhancing mass ſt involving the rectosigmoid colon, with no evidence of colonic obstruction (Right) Axial CECT in the same patient reveals an enhancing perirectal nodal metastasis ſt The patient had a subsequent endoscopic biopsy of the mass, which identified a non-Hodgkin lymphoma (Left) Axial CECT in a 71-yearold man with known lung carcinoma presenting with LLQ pain and a palpable mass demonstrates a large heterogeneously enhancing mass involving the descending colon ſt This was a colonic metastasis (Right) Axial CECT in a 68-year-old man with weight loss and RLQ pain demonstrates a bulky ileocecal mass with smooth margins ſt Note the oral contrast filling the lumen of the cecum st, indicating the lack of obstruction Endoscopic biopsy revealed a high-grade B-cell lymphoma 541 This page intentionally left blank ... NEOPLASMS 13 2 13 6 Lymphangioma (Mesenteric Cyst) Siva Raman, MD Desmoid Siva Raman, MD INFLAMMATION 16 6 17 0 17 2 17 4 17 5 17 6 17 7 DEGENERATIVE 17 8 17 9 18 0 18 4 18 8 19 2 19 4 MALIGNANT NEOPLASMS 14 0 14 4 14 8... DISORDERS 11 4 Portal Hypertension and Varices Siva Raman, MD TRAUMA 11 8 12 0 Traumatic Abdominal Wall Hernia Siva Raman, MD Traumatic Diaphragmatic Rupture Siva Raman, MD TREATMENT RELATED 12 4 12 6 13 0... 16 00 John F Kennedy Blvd Ste 18 00 Philadelphia, PA 19 103-2899 DIAGNOSTIC IMAGING: GASTROINTESTINAL, THIRD EDITION ISBN: 978-0-323-37755-3 Copyright © 2 015 by Elsevier All rights reserved No part