FINE-NEEDLE ASPIRATION CYTOLOGY OF METASTATIC SMALL CALL CARCINOMA OFTHE COLON - A REPORT OF 3 CASES

Small cell carcinoma of the large intestine is a rare, extremely aggre ssive malignancy often associated with an overlying adenoma. We report three cases of metastatic small cell carcinoma of the colon diagnosed by fine-needle aspiration (FNA) biopsy. Two of the patients were wome n (ages 33 and 46 yr old) and one was a man (69 yr old). FNA biopsy Es tablished the diagnosis of metastatic small cell carcinoma involving t he liver (2 cases) and soft tissue of the scapular region (I case). In one patient, the FNA diagnosis of hepatic metastases preceded identif ication of the primary site. Subsequently, the patient was found to ha ve a small cell carcinoma subadjacent to a colonic villous adenoma, il lustrating the importance of investigating villous lesions of the colo n in patients with metastatic small cell carcinoma of unknown primary origin (especially in non-smokers). All three cases showed the charact eristic cytologic features of small cell carcinoma. Ancillary studies performed on aspirated material confirmed the diagnosis of small cell carcinoma in one case, Immunocytochemical studies revealed punctate cy tokeratin and diffuse neuron-specific enolase (NSE) positivity of the malignant cells. Ultrastructurally neurosecretory granules were eviden t To the best of our knowledge, this is the first FNA cytologic report of metastatic small cell carcinoma of the large intestine. This FNA r eport also demonstrates when a small cell carcinoma is detected in a m etastatic sire in a patient lacking a lung primary, a likely primary s ite could be adjacent or beneath a polypoid lesion of the colon. (C) 1 996 Wiley-Liss, Inc.