SMALL CELL (OAT CELL) CANCER OF THE PROSTATE

Cancer of the Prostate Gland; Prostatic Cancer; Prostatic Carcinoma; Small Cell Carcinoma (SCC) of the Prostate

Small cell cancer of the prostate is a rare cancer occurring less than 1% of all cancers of the prostate. They are aggressive tumors that often present at advanced stages or as metastatic diseases and are occasionally associated with paraneoplastic syndromes. Some small cell cancers represent recurrent tumors after hormonal therapy for conventional adenocarcinomas of the prostate. More commonly, small cell cancer is present as a component of mixed tumors, which also contain a component of conventional adenocarcinoma. Small cell cancers of the prostate are similar to the more common small cell cancers of the lung.

They are characterized by the following features:

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  Solid, sheet-like growth pattern, often with areas of tumor necrosis;

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  Small, round to spindle cells with scant cytoplasm, high nuclear/cytoplasmic ration and ill-defined borders;

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  Hyperchromatic nuclei with finely granular chromatin and nuclear molding;

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  Absent or inconspicuous nucleoli; and

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  High mitotic rate.

Diagnostic testing: Small cell cancers are often positive for NE markers chromogranin-A, synaptophysin, and NSE although one or more of these markers may be negative in any given case. Like small cell cancers of the lung, tumor cells often show dot-like cytokeratin staining pattern and are often positive for TTF-1. In contrast to prostatic adenocarcinoma, tumor cells of small cell cancer are usually negative for androgen receptor and prostate-specific antigen (PSA) but exceptions exist.

Physical findings: Small cell cancer of the prostate presents as a solid growth pattern, which makes it difficult to separate from adenocarcinomas, however, immunohistochemical study can help in diagnosing this condition.

ICD-9: 185.0

ICD-10: C61

The progression of small cell cancer of the prostate is usually rapid and fatal.

Hormonal therapy is not effective in treating small cell cancer of the prostate and neither is surgery. The general response to chemotherapy, the main form of therapy for small cell cancer, is some initial response but progressing to a rather rapid downhill course.

Suggested MER for Evaluation:

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  A pathology report of a biopsy specimen from the prostate showing small cell histology. There is no substitute for pathology.

Suggested Listings for Evaluation:

REMARKS

Requires only pathology for adjudication.