Malignant melanoma

Malignant melanoma is a malignant neoplasm that arises from melanocytes (or cells that derive from melanocytes).  

Pathology

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.

Thus, melanoma may be primary or metastatic and the primary form may arise from the skin or (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

  • mucosal melanoma

    • sinonasal mucosal melanoma

• metastatic melanoma

  • intracranial metastatic melanoma

Radiographic features

In general, radiology is useful for identifying metastatic melanomatous deposits.

Treatment and prognosis

Despite being one of the less common types of skin cancer, they cause the majority (75%) of skin cancer-related deaths.

Prognosis is related to stage of disease. Staging for malignant melanoma is accomplished using the American Joint Committee on Cancer (AJCC), 8th edition melanoma staging system which has been in use since January 1, 2018 ⁵.