Clear cell differentiation in choroidal melanoma. COMS report no. 8. Collaborative Ocular Melanoma Study Group.

Daniel Albert // Publications // Jul 01 1997

PubMed ID: 9230830

Author(s): Grossniklaus HE, Albert DM, Green WR, Conway BP, Hovland KR. Clear cell differentiation in choroidal melanoma. COMS report no. 8. Collaborative Ocular Melanoma Study Group. Arch Ophthalmol. 1997 Jul;115(7):894-8. PMID 9230830

Journal: Archives Of Ophthalmology (Chicago, Ill. : 1960), Volume 115, Issue 7, Jul 1997

OBJECTIVE To describe 2 enucleated eyes of patients enrolled in the Collaborative Ocular Melanoma Study that contained primary choroidal melanoma with clear cell features.

METHODS During a 9-year period, 1493 eyes enucleated as part of the Collaborative Ocular Melanoma Study routinely processed for histologic examination were evaluated by the pathology review committee (H.E.G, D.M.A, and W.R.G). Two eyes with unusual variants of choroidal melanoma were identified and immunostained for S100 protein and HMB 45. Portions of the tumors were processed for electron microscopic examination.

RESULTS Results of electron microscopic examination of both tumors displayed malignant melanoma (mixed cell type with many malignant cells with clear cytoplasm). The cytoplasm of the clear cells stained with periodic acid-Schiff and failed to stain when pretreated with diastase. Results of immunohistochemical stains in both tumors were positive for S100 protein and HMB 45 in the tumor cells. Results of electron microscopic examination showed that the cytoplasm of the clear cells contained scattered glycogen granules, premelanosomes, and melanosomes.

CONCLUSION These cases represent a clear cell variant of malignant melanoma of the choroid. This tumor should not be confused with metastatic clear cell carcinoma to the choroid.