Other tumors
Melanoma of bladder

Author: Gillian Levy, M.D. (see Authors page)

Revised: 8 August 2016, last major update December 2014

Copyright: (c) 2003-2016,, Inc.

PubMed Search: Melanoma of bladder [title]
Cite this page: Melanoma of bladder. website. Accessed November 21st, 2018.
Definition / general
  • Primary tumors are rare (< 50 cases reported) and are associated with melanosis; metastases are much more common
  • Ages 44-81 years
  • No gender preference
  • Bladder and urethra
  • Metastatic lesion or primary lesion
Clinical features
  • Almost all reported cases are fatal
  • Gross hematuria is the most frequent presenting symptom
Prognostic factors
  • Metastatic lesions, size and depth of invasion
Case reports
Clinical features
  • Cystoscopy: pigmented raised lesions; the clinical differential diagnosis includes endometriosis, melanoma and sarcoma
Gross description
  • Occurs throughout bladder, variable pigmentation
Microscopic (histologic) description
  • Spindled or epithelioid; epithelioid cells often have marked pleomorphism, abundant cytoplasm, prominent eosinophilic nucleoli
  • Necrosis and mitotic figures common
  • Often atypical melanocytes
Microscopic (histologic) images

Images hosted on other servers:
Missing Image

Metastatic tumor (left: H&E, right: HMB45+)

Cytology description
  • Cells with pleomorphic nuclei singly or in clusters
  • Spindle cells can be seen
  • Often cytoplasmic melanin pigment and prominent eosinophilic nucleoli
  • Malignant cells, some with cytoplasmic melanin; also macrophages containing melanin (Acta Cytol 2001;45:631)
Positive stains
Negative stains
Differential diagnosis
  • Sarcoma, poorly differentiated carcinoma
  • Metastatic melanoma: clinical history of primary, although some primaries spontaneously regress so this may be difficult to conclusively establish; no bladder melanosis