Abstract

Kerion is an inflammatory mass, often characterized by a nodular, boggy appearance secondary to a severe delayed-type hypersensitivity reaction in the setting of dermatophyte infection. The most common location is the scalp, typically in children with tinea capitis. The clinical and radiologic findings can often be extensive with features concerning for soft tissue neoplasms. Here, we present a previously healthy pediatric patient who presented with a recent history of a tender scalp lesion, increasing in size with associated drainage. The mass was approximately 4 cm, fluctuant and painful with surrounding erythema and scaling. Associated lymphadenopathy was also present. Imaging studies revealed an enhancing soft tissue mass without definitive involvement of the underlying calvarium, suspicious for soft tissue neoplasm (such as a sarcoma or vascular neoplasm) versus other etiologies. An excisional biopsy was performed. Histopathologic examination demonstrated a diffuse, predominantly neutrophilic infiltrate involving the epidermis, dermis, and subcutaneous fat with extensive abscess formation and associated suppurative folliculitis. Numerous fungal organisms were present within hair shafts, which were highlighted by Grocott’s Methenamine Silver and Periodic Acid-Schiff staining. The findings were most consistent with Kerion. Furthermore, fungal cultures grew Microsporum gypseum. The patient was subsequently treated with anti-fungal therapy and experienced significant response and near resolution months later. It is our aim to increase awareness of this rare entity, its capacity to mimic soft tissue neoplasms, and to highlight a relatively rare causative agent of Kerion, Microsporum gypseum.

Financial Disclosure:
No current or relevant financial relationships exist.

Financial Disclosure:
No current or relevant financial relationships exist.