Cetuximab-Induced Hidrocystomas: A Case Report

Cetuximab, an EGFR inhibitor, was reported to cause an acneiform eruption in a 70-year-old man treated for metastatic colorectal carcinoma, which improved after stopping the drug but left behind cystic papules and superficial white cysts. A skin biopsy revealed these as hidrocystomas, suggesting that cetuximab may have caused a cutaneous inflammatory reaction leading to sweat duct blockage and cyst formation. This case was the first to describe the resolution of cetuximab-induced acneiform eruptions with residual hidrocystomas and milia.