Late normalization of melanocytomalytic intraocular pressure elevation following excision of iris melanocytoma.

Background: Melanocytoma of the iris is a rare tumor which may sometimes undergo necrosis that could result in elevated intraocular pressure through pigment dispersion. Only nine similar patients have been previously reported.

Methods: A 27-year-old woman presented with a dark brown iris stromal mass located between the 4 and 8 o'clock positions in the inferior quadrant. Her left visual acuity was 20/60. The tumor encroached on the lens and caused focal cataract. There was massive pigmented debris over the iridocorneal angle and the intraocular pressure was 42 mmHg.

Results: Fine needle aspiration biopsy did not suggest malignancy. A wide sector iridectomy was performed and histopathological examination of the lesion revealed melanocytoma of the iris. There was no ciliary body involvement. In the postoperative period, intraocular pressure, which persisted in the mid-twenties, was successfully lowered with topical dorzolamide and betaxolol drops. These drugs were continued for 2 years while the angle pigmentation gradually disappeared. There has been no documented glaucomatous damage to the optic nerve and visual fields. A year after the cessation of the drops, the left intraocular pressure stabilized and did not rise above 15 mmHg. Her left visual acuity remained 20/25.

Conclusion: In contrast to previously reported cases, the normalization of intraocular pressure in this patient took 26 months, a period that could be associated with the self-clearing process of pigment from the iridocorneal angle. Close follow-up with medical treatment averted a pressure lowering surgical procedure in this case.