**4. Clinical vignette #2**

A 26-year-old man reported intermittent blood in his stool for more than 1 year [17]. The patient appeared well nourished and in no distress. Rectal exam demonstrated scarring from previous anal fissures. Stool examination was negative for occult blood, although laboratory testing did suggest a low mean corpuscular volume and total serum iron. During outpatient colonoscopy, a large ulcerated circumferential lesion was identified in the right colon, which was biopsied and submitted to pathology.

The pathology report had indicated "histologically normal colonic mucosa with prominent submucosal lymphoid aggregates, no malignancy identified" [17]. The lesion had a high probability of neoplastic potential, suggesting a possible false-negative biopsy due to inadequate sampling. A surgery consult was ordered as well as an abdominal CT and barium enema. The CT reaffirmed a mass in the area of the cecum, but did not confirm whether the mass was inflammatory or neoplastic; the barium enema highlighted a mass consistent with malignancy. Following the resection of right colon and terminal ileum, pathology identified a moderately differentiated infiltrative cecal carcinoma with negative margins and metastatic carcinoids in 2 out of 24 pericolonic lymph nodes. The patient did well, although treatment was not initiated until 5 weeks after the procedure.
