Undifferentiated carcinoma of the prostate with small cell features: immunohistochemical subtyping and reflections on histogenesis

Virchows Arch. 1999 May;434(5):385-91. doi: 10.1007/s004280050357.


To investigate the histogenesis of undifferentiated carcinoma of the prostate with small cell features we analysed the expression of neuroendocrine (NE) markers, the androgen receptor (AR), and prostate-specific antigen (PSA) in 19 undifferentiated carcinomas of the prostate. The proliferative activity (MIB-1/Ki67) of the tumours was examined, and the clinical data reviewed. The results identified two groups: carcinomas in group 1 were positive for PSA and AR and negative for NE markers. The mean MIB-1 labelling index (LI) was 34.8% and the mean serum PSA value 56.4 ng/ml. Two of the 7 patients died within 12 months after tumour diagnosis. The tumours in group 2 were NE differentiated small cell carcinomas (SCC), which were negative for PSA and AR. The mean MIB-1 LI was 82.6% and the mean serum PSA value 7.1 ng/ml. Seven of the 10 patients died between 2 and 12 months after tumour diagnosis. Positive staining for NE markers in combination with negative staining for PSA and AR and a high MIB-1 LI substantiated the diagnosis of a NE-SCC. We suggest that this tumour has a stem cell origin and does not derive from a dedifferentiated adenocarcinoma or from benign NE cells of the prostatic epithelium. This clear distinction of NE-SCC from NE-negative undifferentiated carcinoma is in accordance with the differing biological behaviour and response to therapy of the two tumour entities.

MeSH terms

  • Adenocarcinoma / chemistry
  • Adenocarcinoma / classification*
  • Adenocarcinoma / pathology*
  • Aged
  • Aged, 80 and over
  • Carcinoma, Small Cell / chemistry
  • Carcinoma, Small Cell / classification*
  • Carcinoma, Small Cell / pathology*
  • Cell Differentiation
  • Chromogranin A
  • Chromogranins / analysis
  • Humans
  • Immunohistochemistry
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Phosphopyruvate Hydratase / analysis
  • Prostatectomy
  • Prostatic Neoplasms / chemistry
  • Prostatic Neoplasms / classification*
  • Prostatic Neoplasms / pathology*
  • Staining and Labeling
  • Synaptophysin / analysis


  • Chromogranin A
  • Chromogranins
  • Synaptophysin
  • Phosphopyruvate Hydratase