Occult anterior uveal melanomas presenting as extrascleral extension

Objective To describe the management of patients with occult anterior uveal melanomas presenting with extrascleral extension. Methods and analysis Retrospective case series including five patients with small pigmented nodular mass on the episclera. Each lesion was documented by slit-lamp photography and measured with high-frequency ultrasound imaging (ultrasound biomicroscopy). Diagnosis of uveal melanoma was confirmed by biopsy with lamellar sclerectomy. Immediate scleral patch graft repair was performed. Later, each tumour was treated with palladium-103 ophthalmic plaque brachytherapy. The mean plaque diameter was 12 mm (median, 12; range, 10-14). A mean apex prescription dose of 87 Gy (median, 84.5; range, 82.3-99.2) to a tumour depth of 2 mm from the inner sclera delivered over 7 continuous days. The main outcome measures were best-corrected visual acuity, changes in tumour and scleral characteristics and complications. Results During each surgery, residual tumour was visualised within an emissary passageway at the deep plane of scleral resection. At a mean of 80 months (median, 57; range, 24-159) follow-up, no patients experienced graft infection, scleromalacia or rejection. Biopsy was required to establish the diagnosis, transillumination failed, and therefore ultrasound measurements were used to determine the plaque size required to treat the relatively occult intraocular component. Despite these challenges, there were no cases of local tumour recurrence, secondary enucleation or metastatic disease. Attributed to cataract surgery, visual acuities improved in three patients and two were stable. Conclusion Extrascleral uveal melanoma extension can occur with undetectable, occult intraocular tumours. In these cases, plaque radiation effectively induced local tumour control, preserved vision and prevented metastasis.