Are most intraocular "leiomyomas" really melanocytic lesions?

BACKGROUND

Intraocular smooth muscle tumors have long been a subject of controversy. The advent of immunohistochemistry with antibodies against HMB-45, S-100, smooth muscle actin, desmin, and vimentin has helped greatly in the distinction between smooth muscle tumors and melanocytic lesions.

METHODS

Twenty-seven archival tissue blocks from patients who had had intraocular leiomyomas or leiomyosarcomas diagnosed were located and fresh sections cut and stained for the above markers. The cases constituted 24 iris lesions and 3 ciliary body lesions.

RESULTS

All 24 iris tumors were reclassified as iris melanocytic lesions. Two of the three ciliary body leiomyomas retained their classification, and the third was reclassified as a spindle B-cell melanoma.

CONCLUSION

The authors suggest that intraocular leiomyomas are much rarer than previously suggested and that many of the cases previously reported in the literature are open to question.