Morphea following treatment with pembrolizumab for melanoma with metastatic lymph nodes: case report and review of literature.

Pembrolizumab is a humanized IgG4 isotype mAb that the targets and blocks the programmed cell death protein 1 receptor on lymphocytes. Its use in treating metastatic melanoma is associated with increased overall survival compared to other older immunotherapies. Several adverse effects have been noted including both systemic and cutaneous manifestations. As a relatively novel treatment option, many new cutaneous manifestations are still being observed, occurring at various times after initiation of therapy. Previously noted cutaneous adverse effects include sarcoid-like reactions, rash, and changes in preexisting lesions or scars. Here we present a case in which biopsy-proven morphea developed after completion of pembrolizumab therapy.