Case 208 - Discussion

Uploaded: 2008-05-03, Updated: 2008-06-21

  • Immunostains:

    • Positive: S100, vimentin, melan A

    • Negative: CD45, CD15, CD30, cytokeratin, CD34

Metastatic Melanoma

  • <5% melanomas are amelanotic;

  • The metastases of pigmented primary melanomas may be amelanotic clinically and histologically;

  • In 3-5% of metastatic melanomas, the primary tumors are not identified;

  • S100: most sensitive but lest specific;

  • Desmoplastic and spindle cell melanomas are most commonly negative for Melan-A and HMB45, but almost always positive for S100.

  • No melanocytic marker can distinguish benign from malignant melanocytic lesions.

Reference: PIP, 2008-A