Eye
Uvea
Uveal melanoma

Editorial Board Member: Kelly Magliocca, D.D.S., M.P.H.
Editor-in-Chief: Debra Zynger, M.D.
Eric M. Tretter, B.S.

Topic Completed: 1 August 2018

Revised: 8 April 2019

Copyright: 2004-2019, PathologyOutlines.com, Inc.

PubMed Search: Uveal melanoma[TI] review[ptyp] pathology

Eric M. Tretter, B.S.
Page views in 2018: 2,740
Page views in 2019 to date: 2,122
Cite this page: Tretter EM, Schoenfield LR. Uvea: uveal melanoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/eyeuveamelanoma.html. Accessed August 24th, 2019.
Definition / general
  • Malignant neoplasm of melanocytes within uveal tract, including iris, ciliary body and choroid
Essential features
  • Tumor center located in iris, ciliary body or choroid (Methods Mol Biol 2014;1102:397)
  • Approximately half metastasize, almost exclusively to liver (Methods Mol Biol 2014;1102:397)
  • Tumor size, location and cell type are the most important histopathologic prognostic factors but molecular testing plays an increasing clinical role in prognostication
Epidemiology
Pathophysiology
Clinical features
  • Half of cases are asymptomatic and discovered on exam; half present with visual disturbance
  • Melanoma of iris: presents as elevated mass with variable pigmentation, often with distortion of pupil and prominent vessels
  • Melanoma of choroid: irregular, slate gray, solid, choroidal tumor that may extend through Bruch membrane into retina and vitreous producing retinal detachment, macular edema, choroidal hemorrhage; occasionally spreads along scleral canals into orbit, rarely invades optic nerve
  • Melanoma of ciliary body: may interfere with accommodation or cause localized cataract
  • Tends to spread through scleral emissary canal
  • Up to half of cases metastasize
  • Lymphatic spread uncommon due to lack of lymphatic channels in eye
Radiology images

Contributed by Arun Singh, M.D., Cleveland Clinic

B scan

Prognostic factors
Case reports
Treatment
Clinical images

Contributed by
Lynn R. Schoenfield, M.D.

Fundoscopy



AFIP images

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Ciliary body tumor

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Orange pigment

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Vessels over tumor are out of focus

Gross description
  • Small uveal melanomas may be difficult to distinguish from a nevus clinically; size criteria are used
  • Gross findings suspicious for melanoma include:
    • Orange pigment
    • Subretinal fluid
    • Tumor thickness > 2 mm
    • Low internal reflectivity on ultrasound examination
Gross images

Contributed by Lynn R. Schoenfield, M.D.

Uveal melanoma



AFIP images
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Heavily pigmented choroidal tumor

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Large transillumination defect

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Ruptured Bruch membrane

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Subretinal hemorrhage and total retinal detachment

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Partially organized hemorrhage

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Amelanotic tumor with retinal detachment


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Extraocular extension

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Iridocyclectomy

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Tumor of ciliary body

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Subluxation of lens

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Extraocular extension

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Vortex vein invasion

Whole mount images

AFIP images
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Tightly packed melanoma cells

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Tumor with exudative retinal detachment

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Uveal tract diffuse tumor

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Choroidal tumor with extraocular extension

Microscopic (histologic) description
  • There are 2 distinct cell types and most tumors contain a combination of the 2:
    1. Spindle B cells: spindle shaped cells with large oval nuclei and distinct nucleoli
    2. Epithelioid cells: large polygonal cells with atypical nuclei, 1 or more prominent nucleoli and sometimes intranuclear pseudoinclusions
  • Note that spindle A cells also exist, which are spindle shaped cells with slender nuclei that lack visible nucleoli; these are typically benign and are the melanocytes of uveal nevi
Microscopic (histologic) images

Contributed by Lynn R. Schoenfield, M.D.

Dome shaped melanoma

Epithelioid cells

Spindle B cells


PAS

HMB45

MelanA

MITF

Positive stains
Negative stains
  • Cytokeratin markers should be negative but may sometimes stain focally
Molecular / cytogenetics description
Differential diagnosis
  • Metastatic carcinoma (especially if amelanotic):
  • Nevi:
    • Small uveal melanomas may be difficult to distinguish from a nevus clinically; size criteria are used
    • Clinical findings suspicious for melanoma include:
      • Orange pigment
      • Subretinal fluid
      • Tumor thickness > 2 mm
      • Low internal reflectivity on ultrasound examination
Board review question #1
Which feature is suspicious for uveal melanoma as opposed to choroidal nevus?

  1. High internal reflectivity on ultrasound examination
  2. Lack of subretinal fluid
  3. Orange pigment
  4. Tumor thickness of 1.5 mm
Board review answer #1
C. Orange pigment

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Board review question #2
Large polygonal cells with 1 or more prominent nucleoli describe which cell type of uveal melanoma?



  1. Epithelioid cells
  2. Intermediate cells
  3. Spindle A cells
  4. Spindle B cells
Board review answer #2
A. Epithelioid cells

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