Abstract
Purpose: :
Although most clinicians and pathologists who have published articles on the frequency of melanocytic choroidal nevi have reported values between 2% and 9% among Caucasian adults, one well known examiner (J.D.M. Gass) reported a frequency of over 20% among Caucasian adults and over 30% among persons older than 50 years of age. No one has ever challenged or explained the discrepancy between the results Gass reported and those reported by other investigators. The purpose of this study was to determine the frequency of melanocytic choroidal lesions ≥ 0.25 mm in diameter in an independent group of Caucasian adults over the age of 50 years.
Methods: :
The authors evaluated 79 newly referred adult Caucasian individuals over the age of 50 years prospectively in their clinical practice, performed detailed fundus examination of every patient, and identified and mapped all discrete melanotic choroidal lesions ≥ 0.25 mm in diameter in each eye.
Results: :
At least one discrete melanotic choroidal lesion was identified in 25 of the 79 patients (31.6%). Fourteen of the 25 patients (56%) had a single lesion in one eye, 6 (24%) had two or more lesions in one eye, and 5 (20%) had one or more lesions in each eye. All of the melanotic choroidal lesions identified in this study were < 1 disc diameter in basal diameter and completely flat (i.e., not detectably thicker than normal choroid at that site by B-scan ultrasonography). The most frequent locations of these lesions were adjacent to vortex vein ampullae and near the inner scleral openings of the scleral foramina for a long ciliary artery or nerve.
Conclusions: :
Because our study identified a similar frequency of melanotic choroidal lesions as the prior studies reported by Gass, we conclude that Gass is likely to have counted small melanotic choroidal lesions without appreciable thickness as melanocytic nevi. We prefer to regard lesions of this type as choroidal melanocytic clusters and reserve the term melanocytic choroidal nevus for small melanotic fundus lesions having a largest basal diameter greater than 1 disc diameter but less than or equal to 5 mm, a maximal thickness greater than that of normal choroid at that site (by B-scan ultrasonography), or both.
Keywords: oncology • tumors • choroid