Cemiplimab-Associated Sinusoidal Obstruction Syndrome.

A 58-year-old woman developed new-onset recurrent ascites after the recent initiation of cemiplimab for the treatment of advanced basal cell carcinoma. A comprehensive serological workup for viral, metabolic, and autoimmune causes was unrevealing. Transjugular liver biopsy demonstrated parenchymal changes consistent with a diagnosis of sinusoidal obstruction syndrome. While this is a condition commonly observed in patients after hematopoietic stem cell transplantation or use of chemotherapeutic agents, it should also be considered in patients who develop new-onset liver dysfunction after the initiation of checkpoint inhibitors.