Successful management of in-transit cutaneous squamous cell carcinoma with anti-PD-1 immunotherapy.

This report describes the case of a 70-year-old man with metastatic squamous cell carcinoma (SCC) of the right lower leg. Soon after definitive surgical management of the primary and nodal metastases with curative intent, he relapsed, developing aggressive in-transit metastatic disease and recurrent nodal disease. The patient was treated with systemic immunotherapy alone, which not only prompted the progressive nodal metastases to regress, but also resulted in a complete response of the in-transit disease. This situation is previously undescribed in the medical literature.