Sebaceous carcinoma of the eyelid in a patient with Muir-Torre syndrome treated with pembrolizumab: A case report

Patients with Muir-Torre Syndrome (MTS) are at increased risk of developing sebaceous carcinomas besides other visceral malignancies. Pembrolizumab is an effective therapy in patients with high microsatellite instability (MSI-H)/mismatch repair deficient (dMMR) tumors. We report a 70-year-old Caucasian man with a diagnosis of MTS who had multiple sebaceous carcinomas. Molecular profiling and immunohistochemical staining of the tumor cells revealed MSI-H/dMMR and high tumor mutational burden (TMB). He did not have evidence of metastatic disease. Following multiple failed local therapies to the left upper eyelid disease, he was treated with four doses of pembrolizumab which resulted in a complete resolution of the lesion. This case shows that Pembrolizumab can provide a complete response in MTS patients with MSI-H/dMMR sebaceous carcinoma. Although promising, this needs to be further validated in clinical trials.