Malignant melanoma

Malignant melanoma is a malignant neoplasm that arises from melanocytes (or cells that derive from melanocytes).  Melanocytes predominantly occur in the basal layer of the epidermis and most melanomas, therefore, arise in the skin.  However, melanocytes do occur in other locations and can give rise to primary melanoma in unexpected locations, e.g. primary uveal malignant melanoma.

In general, radiology is useful for identifying metastatic melanomatous deposits. Despite being one of the less common types of skin cancer, they cause the majority (75%) of skin-cancer-related deaths.

Thus, melanoma may be primary or metastatic and the primary form may arise from skin, or (and much more infrequently) from other sites. Each is discussed separately:

• primary cutaneous melanoma
• primary noncutaneous melanoma
  • meningeal melanoma
  • primary uveal malignant melanoma
  • primary prostatic malignant melanoma
  • primary urethral malignant melanoma
  • sinonasal mucosal melanoma
• metastatic melanoma
  • intracranial metastatic melanoma