Pemetrexed-Induced Pseudocellulitis Reaction With Eosinophilic Infiltrate on Skin Biopsy

Peripheral edema with painful erythema is an increasingly recognized but poorly understood cutaneous adverse reaction to the antifolate agent pemetrexed. It is frequently misdiagnosed as cellulitis, and when it occurs, it is often dose-limiting. The authors report the case of a patient with preexisting lower extremity edema who developed extensive painful, bilateral erythema 5 days after administration of pemetrexed. An eosinophil-rich dermal inflammatory infiltrate was noted histologically. The authors review previously reported cases of pemetrexed-induced pseudocellulitis and discuss possible pathophysiology.