Primary Melanoma of the Lacrimal Sac Treated With Pembrolizumab.

Primary melanoma of the lacrimal sac is a rare entity, with high mortality and a propensity for recurrence. This report details a patient with widely metastatic melanoma discovered after biopsy of abnormal lacrimal sac tissue during routine dacryocystorhinostomy. The patient subsequently underwent local excision and treatment with pembrolizumab. At the time of this writing, it has been 24 months since the original diagnosis with resolution of his lacrimal and orbital lesions and improvement in all metastatic lesions. This case highlights the growing use of cancer genomics and immunotherapeutic agents in orbital aspects of oncology and reinforces the role of a multidisciplinary approach in the treatment of such diseases.