Acral lentiginous melanoma metastases to the vitreous masquerading as uveitis: A case report

Purpose Cutaneous melanoma is the most common malignancy to present with vitreous metastasis. This report describes a case of vitreous metastasis from acral lentiginous melanoma masquerading as intermediate uveitis in a patient undergoing checkpoint inhibitor (CPI) therapy. Observations This is an 86-year-old Caucasian female with Stage III Acral Lentiginous Melanoma of the left heel who was initiated on nivolumab and relatlimab along with intralesional talimogene laherparepvec (TVEC). Eight months later she developed blurry vision and floaters. She was diagnosed elsewhere with unilateral acute intermediate uveitis, leading to discontinuation of immunotherapy and initiation of topical difluprednate. Extensive infectious and autoimmune work-up including MRI of the brain and orbits was negative. Failing to improve, she presented to our hospital. Exam of the right eye showed best corrected visual acuity 20/50, intraocular pressure of 16 mmHg, keratic precipitates, 1+ anterior cells, and 2+ large amelanotic vitreous cells arranged in veils. The left eye was quiet. Vitreous biopsy revealed malignant melanoma cells, confirming metastatic melanoma. The patient underwent a therapeutic pars plana vitrectomy, intravitreal melphalan injection, and ocular radiotherapy, with resolution of vitreous metastasis. Conclusions and Importance Several atypical, red flags in this patient may serve as clinical indicators; history of malignancy with locoregional progression, timing of immune CPI therapy to symptom onset, failure to treatment response, and large white, amelanotic vitreous cells arranged in veils. This case emphasizes the importance of maintaining a broad differential diagnosis in patients with atypical, or treatment resistant uveitis, especially in individuals with known underlying malignancy.