NMS. Casos Clínicos

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Chapter 8 ♦ Lower Gastrointestinal Disorders

Case 8.21  Heme-Positive Stool with Fatigue and Weight Loss

A previously healthy 55-year-old is referred to you for recent onset of fatigue and a 5-lb weight loss. The patient has no other symptoms, and history (past, family, and social) is negative. Review of symptoms is negative. On physical examination, two positive findings are evident: pale conjunctiva and black, guaiac-positive stool. Q: What evaluation is appropriate? A: The patient has suspected colon cancer, particularly of the cecum or right colon because of the anemia and black stools. Identification, localization, and histology of the lesion are necessary. Colonoscopy is best, and it also identifies other colonic pathology such as sec- ond lesions or other disease processes. Colonoscopy has largely replaced barium enema. Figure 8-24 shows a virtual colonoscopy image and coronal CT reconstruction of the colo- noscopic image, in which a tumor is noted on both sides of the colon lumen. A CXR, CEA measurement, and liver function tests are warranted to check for metastatic disease. CT of the abdomen and pelvis is indicated. The current spiral CT scans are highly reliable in detecting liver lesions. Further studies are unnecessary unless organ-specific symptoms are present. Table 8-3 outlines the symptoms of left-sided and right-sided lesions. The patient’s hematocrit is low (30%), and indices demonstrate a microcytic anemia. Serum iron is decreased. Colonoscopy reveals a 5-cm exophytic mass in the cecum. The remaining studies, including CXR, CT, and liver function tests, are normal. A biopsy reveals moderately differentiated adenocarcinoma of the cecum.

A B Figure 8-24: “Apple core” invasive cancer discovered on virtual colonoscopy. A: The virtual colonoscopy image shows a large endoluminal mass (straight arrows), associated with narrowing of the colon lumen (curved arrows). B: Coronal CT reconstruction of the colonoscopic image. The tumor (arrow) is noted on both sides of the colon lumen and extrudes into the pericolic space. (From Farrell TA. Radiology 101: The Basics and Fundamentals of Imaging , 5th ed. 2019, Fig. 3-31.) SAMPLE