Primary small cell carcinoma of the prostate (OAT cell type) – a case report

Abstract

Primary small cell carcinoma of the prostate is a rare anaplastic tumour with poor prognosis. The tumour may be pure small cell carcinoma as seen in lungs or may have a mixed pattern of adenocarcinoma with small cell carcinoma. ations revealed mild anaemia and prostate specific antigen (PSA) of 20.1 ng/mL. Transurethal resection (TUR) of the prostate was done and the tissue was subjected to histopathological evaluation. A diagnosis of small cell carcinoma of prostate was given. There was diffuse homogenous proliferation of small carcinomatous cells which had replaced the normal architecture of the gland. The tumour cells were composed of uniform small cells having a pyknotic round nucleus. The chromatin was evenly distributed. Nucleoli were inconspicuous with scanty cytoplasm. Some of the tumour cells revealed intense granularity of cytoplasm. They were infiltrating the adjacent parenchyma. On immunohistochemistry, the tumour cells stained positive for neuron specific enolase (NSE) and negative for PSA and prostatic acid phosphatase (PAP). The patient died within 6 months because of metastases. Small cell (oat cell) carcinoma of the prostate is a rare aggressive tumour of the prostate with poor prognosis. It has a median survival of 5 months and may or may not co-exist with usual prostatic adenocarcinoma.