melanoma

Introduction

malignant tumor of melanocytic origin.

Etiology

[1]

• cutaneous melanoma (85%)
• other sites (15%)
  • intraocular melanoma (12%)
  • vulva (1%)
  • others (0.1-1%)
    • soft tissues, anus, rectum, vagina, mouth, GI tract, upper respiratory tract, bronchus* (images)
  • others < 0.1%
    • lung, lip, penis, genitourinary, napsopharynx

* melanoma of bronchus probably metastatic from skin despite negative lymph nodes

Immunophenotype

• see melanoma associated antigens (MAGE)

• S100 +
• vimentin +
• HMB45 +
• melan A +
• microphthalmia associated transcription factor (nucleus)
  • most non sarcomatoid +
  • spindle cell/desmoplastic less positive staining

Laboratory

• droplet digital PCR assays detect BRAF V600-mutant circulating tumour DNA
  • a prognostic biomarker for recurrence of melanoma
• see ARUP consult

Management

• surgical resection of solitary pulmonary with no other evidence of disease
  • OpenEvidence would disagree
• immune checkpoint inhibitor is standard first-line treatment for most patients with metastatic BRAF-mutant melanoma, except in cases of aggressive, rapidly progressing disease where targeted therapy (BRAF inhibitor + MEK inhibitor) may be considered for faster disease control
  • treatment of melanoma of the bronchus with trametinib & dabrafenib
    • may be out of date recommendation

More general terms

• melanocytic neoplasm
• sarcoma

More specific terms

• cutaneous melanoma
• intraocular melanoma