A 33-year-old woman was referred to the Ocular Oncology Unit for evaluation of a pigmented lesion in the iris of the right eye (OD) discovered during routine examination. On examination she presented with average myopia in both eyes with a visual acuity of 0.8. The left eye showed no pathological findings, while in the OD there was a rounded pigmented mass of approximately 3-4 mm in diameter in the superoexternal quadrant of the anterior chamber (AC) between the 9 and 11 o'clock meridians. IOP was normal, and gonioscopy showed occupation of the angle by the mass without satellite lesions. Examination under mydriasis showed that it originated in the ciliary body, producing a notch in the transparent lens and a fundus without pathology. Computed Axial Tomography (CT) showed the existence of a rounded mass located between the root of the iris and the ciliary body with moderate contrast uptake, 8.3 mm in height and 7.5 mm in diameter, with no signs of extraocular extension. A diagnosis of probable melanocytoma of the ciliary body was made, and as the patient was asymptomatic and had good visual function, it was decided to observe her periodically. The patient remained stable for 36 months until, coinciding with an episode of corneal erosion due to the use of contact lenses, she developed inflammation in the CA, with the presence of pigment dispersion, excavation of the tumour mass and an increase in IOP that was resistant to the usual medical treatment. This condition was diagnosed as melanocytomalytic glaucoma and surgical treatment was decided. An ab externo iridocyclectomy was performed with excision of the tumour mass. The patient has evolved favourably and after one year maintains a VA of 0.3.
Histopathology revealed a pigmented mass measuring 9x8x8 mm, with a large central necrotic area and the rest composed of densely pigmented, polyhedral cells with a rounded, central nucleus, characteristic of melanocytoma with large areas of necrosis. No atypical cells were found.

