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.

Castleman disease (CD) is a rare heterogeneous lymphoproliferative disorder and presents as unicentric Castleman disease (UCD) or multicentric Castleman disease (MCD). Cutaneous manifestations of MCD are rare and variable. Here, we reported an unusual case of MCD that initially presented with localized plaques on the scalp.

Pyoderma gangrenosum (PG) is an inflammatory dermatosis characterized by the rapid progression of a painful, necrolytic ulcer with an irregular and undermined border. The prevalence of PG in patients with Crohn’s disease (CD) has been estimated to be 0.7%. Here, we report a case that presented various painful skin lesions, including erythema, vesicles, plaques, and ulcers, one week before the fourth infliximab infusion for CD. PG was diagnosed and the lesions subsided after a 390-mg ustekinumab infusion for one month. It suggests that different lesions of PG may occur concomitantly in CD patients, and the therapy should be re-evaluated on time.