Bullous Pilomatricoma After Influenza Vaccination.

Pilomatricoma, also known as "benign calcifying epithelioma", is an uncommon slow-growing benign adnexal skin tumor, which originates from primitive cells of the hair matrix and usually appears as a solitary, firm, and asymptomatic nodule beneath the skin. Bullous pilomatricoma is a rare form of pilomatricoma, always presenting with firm subcutaneous nodules with a bullous appearance. In this study, we report a 9-year-old Chinese presenting girl with bullous pilomatricoma after influenza vaccination.