Erythema nodosum-like panniculitis associated with immune checkpoint inhibitor therapy: Two cases reporting a rare cutaneous adverse event

Erythema nodosum (EN) is the most common form of panniculitis and typically presents as painful erythematous nodules on the shins, and may be associated with systemic symptoms including fever and arthralgia.1,2 Histopathology demonstrates septal panniculitis with an inflammatory infiltrate, which includes neutrophils in the early stage and lymphocytes and multinucleated giant cells in the late stage.1 A wide variety of etiologies are associated with EN, including infections, sarcoidosis, rheumatologic disorders, inflammatory bowel disease, autoimmune disorders, medications, and malignancies.