Optic disc melanocytoma with normal tension glaucoma and angle closure glaucoma: Two case reports.

RATIONALE

Optic disc melanocytoma is an ophthalmic tumor that arises from melanocytes, and is a variant of the melanocytic nevus. Here we report 2 cases of optic disc melanocytoma in Asian patient: one associated with normal tension glaucoma (NTG), and the other associated with angle closure glaucoma (ACG).

PATIENT CONCERNS

Case 1 is a 57-year-old Asian female presented to our department for a general ophthalmic examination. Incidentally, brownish pigmented lesion was found on dilated fundus examination of her right eye. The fundus examination and optical coherence tomography (OCT) examination revealed a mass within optic disc, and superotemporal retinal nerve fiber layer (RNFL) thinning. The Humphrey visual field test showed corresponding visual field defect. Fluorescein angiography showed no leakage around the lesion. Case 2 is a 78-year-old Asian woman presented with complaints of acute bilateral ocular pain. The initial examination revealed shallow anterior chamber. Under the impression of intermittent angle closure attack, prophylactic laser peripheral iridotomy were performed. On dilated fundus examination, black pigmented lesion was found at superior sector of optic disc. Further examination revealed bilateral superotemporal, inferotemporal RNFL thinning on OCT, and spatially corresponding visual field defects.

DIAGNOSES

Clinical diagnosis of NTG was made for case 1 patient. Although it was a little distant from typical glaucomatous changes, nevertheless she had RNFL defect compatible with visual field defects. Considering her normal IOP and angle structures, we believe NTG was a probable diagnosis for the patient. In case 2, we made diagnosis of ACG presenting as intermittent angle closure attack because of her presenting symptoms, narrowing of anterior chamber and angle structures found on gonioscopic and slit lamp examinations.

INTERVENTIONS

In Case 1, we prescribe 0.005% latanoprost ophthalmic solution. In Case 2, at first prophylactic laser peripheral iridotomy was performed. Then, topical eyedrops administration was started, and the patient was examined periodically.

OUTCOMES

In Case 1, at 6 months' follow-up, OCT and visual field test showed no progression. In Case 2, to this date, the optic disc melanocytoma remains stable for over a 6-year-follow-up period.

LESSONS

The fact that NTG and ACG can coexist in patients with melanocytoma of optic disc should be recognized, and the possibility of such should appropriately be evaluated.