Neurofibromatosis type 1 and melanoma of the iris arising from a dysplastic nevus: A rare yet casual association?

Purpose: We investigated the molecular causes of an unusual pigmented and ulcerated iris lesion detected in a patient diagnosed with neurofibromatosis type 1 (NF1). Case Report: A 52-year-old man was referred to our clinic with a non-traumatic ulcer in his left eye. Hyphema reabsorption disclosed a pigmented iris mass, thus ultrasound biomicroscopy and anterior segment fluorescein angiography were performed to investigate for the presence of a malignant lesion. Upon angiography, the lesion appeared highly vascularized but prevented posterior iris examination. Therefore, a gonioscopy was executed revealing extension of the lesion into the peripheral iris. Histopathology of the excisional iris biopsy revealed iris melanoma over a dysplastic nevus. NF1 is an autosomal dominant disorder characterized by pigmented cutaneous lesions, multiple skin tumors, and spinal and cranial nerve tumors. Uveal melanoma is the most common primary intraocular malignancy in adults. Up to 92% of cutaneous melanomas occur in patients with dysplastic nevus syndrome. Skin melanomas have been found in 0.1%–5.4% of NF1 patients. In literature, only 18 reports of uveal melanoma have been documented in association with NF1, including three cases of iris melanoma. Results: NF1 gene testing identified a causative mutation in the germline but no loss of the wild-type allele in the iris melanoma. Conclusions: Occurrence of both diseases in one patient is extremely rare, but the common origin of Schwann cells and melanoblasts suggests a non-casual association. Therefore, we propose that NF1 patients should be screened for nevi, both cutaneous and uveal, for better patients’ management