|Patient: 45 year old male|
45 year old male
Comapnion case 56 Y old female
Ba. Enema did not pass beyoned the level of the hepatic flexure in the single contrast study, insuflation of the colon by air better demonstarted the irregular edge of the mass, No contrast passed to the cecum or ascending colon.
Complemnatry US revealed a rounded soft tissue mass in the region of the hepatic flexure.
The patient did not present clinical with signs of bowel obstruction nor conistipation.
CT showing a constricting soft tissue mass with haziness of the pericolic fat denoting early local spread
|Diagnosis: Adenocarcinoma of the colon|
Colorectal adenocarcinoma is the most common malignancy of the GI tract and the second most common malignant tumor in the United States. Approximately 50% arise in the rectum and rectosigmoid area. Another 25% occur in the sigmoid colon, and the remaining 25% are evenly distributed throughout the remainder of the colon. Nearly all cancers of the colon are adenocarcinomas arising from preexisting adenomas. Most tumors are annular constricting lesions, 2 to 6 cm in diameter, with raised everted edges and ulcerated mucosa. Polypoid tumors are less common, with some having the frondlike appearance of villous carcinoma. Infiltrating scirrhous tumors”common in gastric carcinoma”are rare in the large intestine, unless the patient has ulcerative colitis. The tumor spreads by direct invasion through the bowel wall into pericolonic fat and adjacent organs, through lymphatic channels to regional nodes, and hematogenously through the portal veins to the liver and systemic circulation. Intraperitoneal seeding from a tumor that penetrates the colon wall may also occur. Obstruction is the most frequent complication. Other complications are uncommon but include perforation, intussusception, abscess, and fistula formation. Up to 20% of patients have a second tumor of the large bowel at diagnosis, usually an adenoma or another carcinoma. Approximately 5% of patients will have a second colorectal carcinoma, either simultaneously or diagnosed subsequently. Patients with ulcerative colitis, Crohn disease, familial adenomatous polyposis syndrome, and Peutz-Jeghers syndrome are at increased risk of colon carcinoma.
Local disease staging is best evaluated with transrectal or colonoscopic US. CT and MR are used for more advanced disease and to detect recurrence. Microscopic invasion through the bowel wall and tumor involvement of normal-size lymph nodes are not detected by CT or MR. Cross-sectional imaging findings include:
(1) polypoid primary tumor (usually >1 cm)
(2) "apple-core" lesions, with bulky, irregular thickening of the colon wall and irregular narrowing of the lumen
(3) cystic, necrotic, and hemorrhagic areas within the tumor mass, especially when the tumor is large
(4) linear soft tissue stranding into the pericolonic fat, which is often indicative of tumor extension through the bowel wall
(5) enlarged regional lymph nodes (>1 cm) representing lymphatic spread of tumor
(6) distant metastases, especially in the liver.
When tumors cause colonic obstruction, edema and/or ischemia may thicken the wall of the uninvolved colon proximal to the tumor.
Tumor recurrences are most common
(1) at the operative site, near the bowel anastomosis
(2) in lymph nodes that drain the operative site
(3) in the peritoneal cavity
(4) in the liver and distant organs.
Because the entire abdominal cavity must be surveyed to detect tumor recurrence, CT is the current method of choice.
Editors: Brant, William E.; Helms, Clyde A.
Title: Fundamentals of Diagnostic Radiology, 3rd Edition
Copyright 2007 Lippincott Williams & Wilkins
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Case Number: 45914547Last Updated: 08-20-2010 The reader is fully responsible for confirming the accuracy of this content.
The reader is fully responsible for confirming the accuracy of this content.