Locally Invasive Diffuse Iris Ring Melanoma Presenting as Unilateral Severe Glaucoma: Case Report and Review of Molecular Genetics

We report the clinical history and histopathological findings in a case of diffuse iris ring melanoma (DIM) and review the most recent literature and modern molecular genetics of this entity. An 85-year-old Hispanic man presented with severe unilateral glaucoma, managed at an outside institution for 2 years prior to presentation. Diffuse pigmentation was noted in the angle, on the intraocular lens implant, and in the vitreous without clear demonstration of a mass on ultrasound biomicroscopy. Workup for metastatic cutaneous melanoma was negative. Histopathological examination of the enucleated eye revealed a mixed cell type iris ring melanoma with diffuse intraocular involvement. Gene expression profiling (GEP) revealed a class 2 molecular signature indicating a very high risk for metastases. Unilateral glaucoma presenting with marked pigmentation in the anterior chamber angle should be managed as melanoma until proven otherwise. Iris ring melanomas are known to have an aggressive clinical course, and recent molecular analyses indicate that they are likely primarily GEP class 2 with a very poor prognosis, similar to the majority of ciliary body melanomas.

Isolated Ocular Sarcoidosis Mimicking Ring Melanoma

We report the case of a 25-year-old female, who presented with a large, pale tumor of her ciliary body that extended to >180° of the anterior chamber angle. All preoperative examinations including ultrasound biomicroscopy, scleral transillumination, and MRI indicated melanoma. A thorough systemic work-up was negative. A diagnosis of ring melanoma was suspected, and the patient was scheduled for enucleation. However, perioperative frozen section indicated granulomatous inflammation. The enucleation was cancelled, and a subtenon injection of triamcinolone was administered, which resulted in the disappearance of the tumor. Together, the findings meet the criteria for the diagnosis of isolated ocular sarcoidosis. This case demonstrates that a sarcoid granuloma can mimic all clinical features of a ring melanoma. Therefore, a biopsy should be done before destructive surgery is carried out.

A Case of Iris Melanocytoma Demonstrating Diffuse Melanocytic Proliferation with Uncontrolled Intraocular Pressure

We report a rare case with histologically proven melanocytoma of the iris that demonstrated diffuse melanocytic proliferation with uncontrolled secondary glaucoma and investigate the etiology of the intraocular pressure elevation. The patient was a 78-year-old man with a history of darkened iris of his left eye. The intraocular pressure was 39 mm Hg. A slit-lamp examination showed a diffuse darkened iris, and a gonioscopic examination revealed open angle with circumferential heavy pigmentation. There was no pigment dispersion of the anterior chamber and no pigment deposition of the cornea. We suspected malignant ring melanoma in the left eye and enucleated it. The globe was examined with light and electron microscopy. Light microscopy revealed the presence of heavily pigmented tumor cells in the iris, ciliary body, trabecular meshwork, and Schlemm’s canal. A bleached preparation showed large tumor cells with central and paracentral nuclei without mitosis. Electron microscopy of the trabecular meshwork revealed melanin-bearing tumor cells invading the intertrabecular spaces, and the melanin granules were not phagocytosed in the trabecular cells. The mechanical obstruction of the aqueous flow by the tumor cells may be a major cause of secondary glaucoma in eyes with iris melanocytoma presenting diffuse proliferation.