Kidney tumor
Renal pelvic tumors
Small cell neuroendocrine carcinoma

Author: Nicole K. Andeen, M.D.
Editor: Maria Tretiakova, M.D.

Revised: 19 April 2018, last major update July 2015

Copyright: (c) 2003-2018,, Inc.

PubMed Search: Small cell neuroendocrine carcinoma [title] kidney

Cite this page: Andeen, N.K. Small cell neuroendocrine carcinoma. website. Accessed December 11th, 2018.
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

Images hosted on PathOut server:

Large invasive tumor

Images hosted on other servers:

Urothelial small cell

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

Images hosted on other servers:

Mixed with urothelial carcinoma

Small cell neuroendocrine tumor

Various images

Minimal cytoplasm,
nuclear molding,
indistinct nucleoli

Absence of nucleoli and high mitotic activity

CD56, synaptophysin, TTF1


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)
Additional references