Home Education AUAUniversity Education Products & Resources Pathology for Urologists Urinary Bladder Non-urothelial Carcinomas Small Cell Carcinoma

Small Cell Carcinoma

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Image B

  • Rare, represents <1% of bladder tumors.
  • Hematuria is a common presenting complaint and may have paraneoplastic syndromes (e.g. hypercalcemia, hyperphosphatemia, ACTH secretion).
  • Usually a large polypoid tumor with extensive bladder infiltration.
  • Histology:
    • Indistinguishable from small cell carcinoma of other organs such as lung and prostate
      (image A), (image B), & (image C).
    • Sheets of small round blue cells that infiltrate in a diffuse pattern.
    • Cells have nuclei with "salt and pepper" chromatin (dusty appearance with inconspicuous nucleoli).
    • Crush artifact (smearing of cells) and nuclear molding is common.
    • High mitotic activity, apoptosis and necrosis common.
    • About half occur mixed with urothelial carcinoma.

Image C

Image D

  • Immunohistochemistry:
    • Express neuroendocrine markers synaptophysin (image D) or chromogranin, which confirm the diagnosis.
    • ~ Half express marker for lung TTF1 (beware).
  • Poor prognosis, with 5-year survival as low as 10%.