Intraabdominal desmoplastic small cell tumor mimicking adenocarcinoma. A case report

BACKGROUND: Fine needle aspirates and washings from intraabdominal desmoplastic small cell tumors (IADSCTs) are rarely encountered by pathologists. Immunocytochemical examination of histologic material is usually necessary for a definitive diagnosis. CASE: A 23-year-old man presented with abdominal pain, ascites and bilateral pleural effusion. Examination of ascitic fluid suggested adenocarcinoma, but histologic and immunocytochemical examination of surgically resected tissue showed features of an IADSCT. CONCLUSION: This case is a reminder that IADSCT should be included in the differential diagnosis of intraabdominal neoplasms and that its diagnosis in cytologic preparations requires a high index of suspicion. In particular, this case appears to be the first reported example of IADSCT mimicking adenocarcinoma.