Primary small cell carcinoma of the cecum.

Cecal extrapulmonary small cell carcinoma (cESC) is extremely rare, with only single previous report of occurrence in a child. We report a 76-year-old man admitted for evaluation of a cecal mass seen in colonoscopy. Histology revealed small cell carcinoma with classic immunohistochemical profile similar to those seen in the colon. Further clinical survey documented absence of any other masses or abnormality. To the best of our knowledge, this is the first case of primary cESC occurring in an adult. Awareness of the pathologist and clinician of the cecum as a potential site of cESC may help to prevent misdiagnosis as poorly differentiated adenocarcinoma. This is crucial because extrapulmonary small cell carcinomas usually have worse prognosis.