Benign melanomas of the ciliary body are rarely found, and then usually accidentally during the routine examination of serial sections. The pathologic diagnosis can at times be difficult. One should differentiate the circumscribed, sharply defined, pigmented, tumor-like area that can be called a pigmented nevus or benign melanoma from the diffuse pigmentation present in association with general ocular melanoses and from those local diffuse pigmentations, sometimes in the form of streaks, that one often finds normally in the ciliary body of eyes otherwise not excessively pigmented.
Normally, the ciliary body contains some pigmented cells in its stroma. The degree of pigmentation depends not only on the number of pigmented cells present, but on the amount of pigment granules present in these cells and the color of the granules themselves. These vary with age, sex and type. Brunettes, as a rule, possess pigmented cells containing relatively more and darker
ALEXANDER B. THE PATHOLOGY OF MELANOSIS AND OF BENIGN MELANOMAS OF THE CILIARY BODY. Arch Ophthalmol. 1932;7(4):521–537. doi:10.1001/archopht.1932.00820110033004