AIPGMEE 2014- 2015

Characteristics of choroidal melanoma include all of the following except
a. choroidal excavation
b. high internal reflectivity
c. double circulation
d. orbital shadowing
Ans=b. high internal reflectivity
Ref-(thanks to the publisher)

Retina

by Stephen J. Ryan

5th edition published by Elsevier

Gross appearance of choroidal melanoma

The gross examination of intraocular tumors is the basis for clinicopathologic correlations as it allows for a detailed macroscopic evaluation and measurement of the tumor size including the prognostically relevant largest basal diameter.^5,6 The largest basal diameter can be reliably assessed on gross examination, although the tumor size may be underestimated when measured after fixation due to tumor shrinkage.⁷Choroidal melanomas exhibit an oval or fusiform shape (Fig. 142.2) when confined by Bruch’s membrane or a collar-button/mushroom configuration (Fig. 142.3) when the tumor has broken through Bruch’s membrane.

FIG.142.2 

(A) Oval-shaped, heavily pigmented choroidal melanoma (molecular profile class I) in a 66-year-old man. (B) Histologically, a mixed-cell type melanoma (asterisk) is present within the uvea (H&E, ×40). Bruch’s membrane (arrow) is intact, the overlying RPE and retina display atrophic changes.

FIG.142.3 

(A) Collar-button shaped pigmented choroidal melanoma in a 70-year-old woman. (B) Histologic examination shows the tumor breaking through Bruch’s membrane (arrow) (H&E, ×40).

Ocular structures may be invaded by choroidal melanomas. Invasion into the ciliary body may be detected macroscopically, whereas invasion into the sclera, retina, and optic nerve as well as invasion into the vitreous, iris, and anterior chamber is usually detected by microscopic examination. Extraocular extension (Fig. 142.4) usually occurs along vortex veins or emissary canals and, dependent on the extent, may be diagnosed clinically or on gross examination.

FIG.142.4 

An 86-year-old woman presented with (A) extraocular extension of a uveal melanoma (molecular profile class II). (B) On gross examination, extraocular extension (arrow) of a mildly pigmented bilobulated tumor was detected that invades the choroid and the ciliary body. (C) Histologic examination (H&E, ×10) shows the extraocular part of the tumor (asterisk) composed of epithelioid cells. The patient died from liver metastasis less than 1 year after enucleation.

The amount of pigmentation of uveal melanomas varies from tumor to tumor or even within a single tumor and may be related to overall survival.^5,8 Most tumors exhibit mild to moderate pigmentation, although heavily or non-pigmented (amelanotic) choroidal melanomas (Fig. 142.5) may be observed.