[Relative contraindication of latanoprost in iris tumors with secondary glaucoma].

INTRODUCTION: Melanocytic iris tumors are often benign and merely require regular follow-up. Evident growth, increasing pigmentation and secondary glaucoma, however, are possible signs of a malignant transformation. PATIENT: We present a 34-year-old male patient showing a localized, mildly prominent hyperpigmentation of the right iris expanding over 2 h. The lesion had been known since childhood and increasing intraocular pressure (IOP) was treated with timolole, dipivefrin and finally with latanoprost. PROGRESSION: The patient was seen for the first time at our hospital 4 years previously, presenting an IOP of 28-30 mmHg of the right eye. The tumor had developed marked heterochromia and a nodular prominent surface, the chamber angle was partly closed and completely hyperpigmented. The ciliary body was not affected by the tumor and standard ultrasound revealed a maximum thickness of 1.2 mm. Over the last 4 years, IOP and heterochromia had increased but without growth of the tumor. An excisional biopsy of the prominent portion was refused by the patient. DISCUSSION: The melanocytic iris tumor described shows malignant characteristics such as progressive heterochromia and secondary glaucoma. However, increasing iris pigmentation can also be caused by topical application of latanoprost. With the evidence of absent tumor growth, there is no reason to suggest malignant degeneration. Generally, in iris naevi or tumors requiring regular follow-up, application of latanoprost should be avoided in order not to conceal the alteration of pigmentation as possible malignant conversion.