Microscopic Description:

General histologic features:

  • Solid sheet-like, nested and trabeculae
  • Small to medium sized cells with scanty cytoplasm and with a high N:C ratio)
  • Stippled salt and pepper chromatin
  • Absent or inconspicuous nucleoli
  • Nuclear molding
  • Azzopardi phenomenon (crush artifact)
  • Brisk mitotic activity and atypical mitoses
  • Extensive necrosis

Frequently coexists with other malignant cell populations 

Positive stains:

  • Synaptophysin
  • Chromogranin A
  • CD56
  • Neuron specific enolase (NSE) (most sensitive)
  • CAM 5.2
Discussion:

Small Cell Carcinoma (SCC) of the bladder:

  • Rare and aggressive neuroendocrine neoplasm
  • Classified into carcinoid tumor and neuroendocrine carcinoma

Neuroendocrine carcinoma subdivided into:

  • Small cell carcinoma (SCC)
  • Large cell neuroendocrine carcinoma (rare in the bladder)

Poorly differentiated

Rarely associated with paraneoplastic syndromes unlike lung SCC

Accounts for 0.5% to 1% of all primary urinary tumors

SCC found extrapulmonary in various organs:

  • Includes esophagus, stomach, pancreas, gallbladder, cervix, kidney, bladder, and prostate

Pure SCC makes up only 0.48% to 1% of all bladder carcinomas

References:

Eshraghi A, Riyahi MM,Ghaderi A, Fatemi MA, Eshraghi A, Fazilat- PanahD. Pure small cell neuroendocrine carcinoma ofurinary bladder: A case report. Clin Case Rep.2022;10:e06156. doi: 10.1002/ccr3.6156

Chraïbi M, Barqui M (2019) Small Cell Neuroendocrine Carcinoma of the Urinary Bladder: Rare Entity Associated to Poor Prognosis. Int Arch Urol Complic 5:055. doi.org/10.23937/2469-5742/1510055.

https://www.pathologyoutlines.com/topic/bladdersmallcell.html

CASE IMAGES