Bladder, ureter & renal pelvis

Neuroendocrine neoplasms

Small cell neuroendocrine carcinoma

Last author update: 1 July 2015
Last staff update: 11 August 2023 (update in progress)

Copyright: 2003-2023,, Inc.

PubMed Search: Small cell neuroendocrine carcinoma [title] kidney

Nicole K. Andeen, M.D.
Maria Tretiakova, M.D., Ph.D.
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Cite this page: Andeen NK, Tretiakova M. Small cell neuroendocrine carcinoma. website. Accessed November 29th, 2023.
Definition / general
  • High grade neuroendocrine neoplasm resembling small cell carcinoma of other organs
  • Pure or admixed with high grade urothelial carcinoma of the kidney
  • Rare, < 1% of renal neoplasms, ~ 50 cases reported
  • Very rarely has been reported with renal cell carcinoma (J Urol 1998;159:1624, Gerontologist 1991;31:631)
  • Likely arises from a multipotent stem cell
Clinical features
Radiology description
Case reports
Gross description
  • Unifocal, centered in renal pelvis, usually invading perinephric adipose tissue (Hum Pathol 2011;42:1792)
  • Median size 11 cm, mean 7.1 cm in another study (range from 2.3 to 23 cm)
Gross images

Contributed by Nicole K. Andeen, M.D. and AFIP images

Urothelial small cell

Large invasive tumor

Images hosted on other servers:

In renal pelvis

Microscopic (histologic) description
  • Similar morphology to small cell carcinoma of the lung
  • Diffuse growth of small cells with minimal cytoplasm, nuclear molding, indistinct nucleoli, high mitotic activity and apoptosis, lymphovascular invasion, necrosis
Microscopic (histologic) images

Contributed by Nicole K. Andeen, M.D.

Mixed with urothelial carcinoma

Minimal cytoplasm,
nuclear molding,


Images hosted on other servers:

Small cell neuroendocrine tumor

Absence of nucleoli and high mitotic activity

CD56, synaptophysin, TTF1


Cytology images

Contributed by Bonnie Choy, M.D.
Small cell carcinoma

Small cell carcinoma

Negative stains
Electron microscopy description
Molecular / cytogenetics description
  • In urinary bladder, studies of coexistent urothelial carcinoma and small cell carcinoma show very similar loss of heterozygosity and X-inactivation patterns, suggesting that urothelial and small cell components derive from same cells in the urothelium, rather than transformation from a population of normal neuroendocrine cells (Am J Pathol 2005;166:1533)
Differential diagnosis
Additional references
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