Ring melanoma of the ciliary body: clinical and ultrasound biomicroscopic characteristics

Abstract Background: Diagnosis of ring melanoma is clinically difficult since the mass can remain hidden with standard slit-lamp biomicroscopy. The aim of this study was to evaluate the utility of ultrasound biomicroscopy (UBM) as a diagnostic tool for ring melanoma of the ciliary body. Methods: This was a retrospective study of 6 eyes of 6 patients at Princess Margaret Hospital,Toronto, Ont., with a diagnosis of ring melanoma of the ciliary body. The tumor extension was measured clinically, gonioscopically, ultrasonographically (by UBM), and pathologically. Results: Since 2000, 6 cases of ring melanoma have been diagnosed at Princess Margaret Hospital: 2 women and 4 men, median age 57 years. Five patients presented as uncontrolled hyperchromic glaucoma (83%). Ciliary body involvement on slit-lamp examination ranged from 60° to 180°. Ciliary body involvement as assessed by UBM ranged from 180° to 300°. Tumor extension according to pathological examination ranged from 210° to 360°. With these measures, the ring melanoma clinical criteria were not filled by 5 patients. Interpretation: UBM is an important tool in determining the extent of ciliary body involvement and classifying these lesions.