Metastatic Melanoma

Esther Oliva, MD

Key Facts

Clinical Issues

History of melanoma may be remote

Macroscopic Features

Bilateral or unilateral and multinodular
Black cut surface due to pigment content

Microscopic Pathology

Diffuse or nodular growth > nested (nevoid)
Follicle-like spaces
Large cells with abundant eosinophilic or, less commonly, clear cytoplasm and pseudoinclusions
Focal intracytoplasmic melanin pigment common

Ancillary Tests

HMB-45, Melan-A (MART-1), S100 positive

Top Differential Diagnoses

Primary malignant melanoma
Steroid cell and granulosa cell tumors
Pregnancy luteoma

Metastatic malignant melanoma has a vague nodular appearance and may show a strikingly black cut surface due to the presence of melanin pigment.

Metastatic melanoma most often grows in sheets, and the cells have abundant eosinophilic cytoplasm, marked nuclear pleomorphism, and mitoses. Notice intracytoplasmic melanin pigment

TERMINOLOGY

Synonyms

Malignant melanoma

Definitions

Malignant melanocytic neoplasm secondarily involving 1 or both ovaries typically due to hematogenous spread

CLINICAL ISSUES

Epidemiology

Incidence
- Relatively common finding at autopsy (up to 18%)
- Rare finding in living patients
- More common than primary ovarian melanoma
Age
- Wide range (mean: 37 years)