Choroidal amelanotic melanoma in a patient with oculocutaneous albinism, a case report

Abstract

The aim of this case report is to describe a rare case of jumbo choroidal amelanotic melanoma in a patient with oculocutaneous albinism treated with stereotactic radiotherapy. A 32 years old, Caucasian male, with oculocutaneous albinism, was admitted to our Ocular Oncology Center of Pisa in February 2018. Slit lamp examination of the left eye showed iris transillumination defects and nystagmus. Funduscopic examination revealed a blonde fundus and a poorly pigmented solid lesion that took up the upper half of the vitreous chamber and touched the lens. B-scan and A-scan ultrasound revealed a mushroom shaped lesion that broke through Bruch’s membrane measuring 15 mm in thickness, 8 mm in basal diameter, low internal reflectivity, and regular structure. The clinical and imaging features suggested a diagnosis of jumbo choroidal amelanotic melanoma. The patient was treated with stereotactic radiotherapy with Volumetric-Modulated Arc Therapy (VMAT) with flattening filter-free (FFF) on a VarianTM TrueBeamSTx, 27 Gy in a single fraction. At the 3-month follow-up visit, the tumor showed an exudative retinal detachment which was treated with an intravitreal injection of bevacizumab. At the 5-month follow-up visit slit lamp examination showed cataract, and iris rubeosis. The tumor demonstrated slight regression from 15 mm to 12 mm in thickness. After 17 months from the treatment the lesion was greatly reduced from 12 mm to 5 mm in thickness. Regular systemic assessments including abdominal ultrasound and chest RX were performed and patient was healthy with no signs of systemic metastatic disease. Although rare patients with oculocutaneous albinism may develop uveal melanoma and stereotactic radiotherapy can represent a valid alternative treatment in jumbo melanoma.