Which histologic findings are characteristic of choroidal melanoma?

Updated: Dec 12, 2018
  • Author: Enrique Garcia-Valenzuela, MD, PhD; Chief Editor: Andrew A Dahl, MD, FACS  more...
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Answer

Histologic evaluation of the tumor after enucleation can confirm the diagnosis and determine the prognosis (see the images below). [6]

Histologic section of an enucleated eye showing a Histologic section of an enucleated eye showing a large dome-shaped choroidal melanoma.
Histologic section of an enucleated eye showing a Histologic section of an enucleated eye showing a medium-sized mushroom-shaped choroidal melanoma with associated exudative retinal detachment.

As noted (see Pathophysiology), 3 distinct cell types are recognized to occur in uveal melanomas: (1) spindle A, (2) spindle B, and (3) epithelioid. Spindle A cells have elongated nuclei and uncommonly have mitotic figures (see the image below).

Choroidal melanoma. Histologic section showing spi Choroidal melanoma. Histologic section showing spindle A cells in a uveal nevus.

Spindle B cells have a prominent nucleolus (see the image below). They are found more commonly and also have an elongated profile but are slightly larger than spindle A cells.

Choroidal melanoma. Histologic section showing spi Choroidal melanoma. Histologic section showing spindle B cells in a uveal melanoma.

Epithelioid melanoma cells are highly anaplastic, poorly cohesive, and have considerable morphologic variation (see the figure below). They tend to resemble epithelial cells and contain frequent mitotic figures.

Choroidal melanoma. Histologic section showing epi Choroidal melanoma. Histologic section showing epithelioid cells in a uveal melanoma.

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