Bladder, ureter & renal pelvis
Other tumors
Malignant melanoma

Topic Completed: 1 December 2014

Minor changes: 1 August 2020

Copyright: 2003-2020,, Inc.

PubMed Search: Melanoma of bladder [title]

Page views in 2019: 369
Page views in 2020 to date: 207
Cite this page: Levy G. Malignant melanoma. website. Accessed August 15th, 2020.
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

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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
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