Primary small cell carcinoma of prostate

Abstract

Primary small cell undifferentiated carcinoma (scuc) of prostate is rare. It may occur in pure form or in combination with adenocarcinoma (adenoca). Since the presence of small cell component is indicative of aggressiveness of the tumour, its recognition is prognostically important. We have seen 4 cases of scuc of prostate from 1987-90. Patient’s age ranged from 65-82 yrs. All but one died of widespread metastases within 2 years. Of these 4 cases, 2 were pure scuc, in 1 of them the diagnosis was made on trucut biopsy and subsequent transurethral resection (TUR) specimens and in the other case the small cell nature of the tumour was not recognised until autopsy as the initial diagnosis based on fine needle aspirate (FNA) was poorly differentiated adenoca. The 3rd case was a composite adenoca. and scuc. The adenoca. was diagnosed with prostate FNA and the small cell component was not detected until autopsy. The 4th case showing a mixed adenoca. and scuc on TUR specimens is alive without evidence of metastasis 4 months after diagnosis. Immunostains of small cells showed variable reactivities of PSAP, bombesin, NSE and chromogranin and negative reaction to calcitonin and ACTH. Electron microscopy showed sparsely granulated cytoplasm. In conclusion, (1) The value of FNA in detecting scuc of prostate is limited. (2) the prostate should be considered the likely primary site in an elderly man who has metastatic scuc especially in the liver and whose lungs are clear.