A Case of a Follicular Hybrid Cyst

Abstract

Various cutaneous cysts such as epidermal cysts, trichilemmal cysts, vellus hair cysts, steatocystoma, or pilomatricoma can arise from a different part of the pilosebaceous unit, namely the infundibulum, isthmus, sebaceous ducts, and bulbar or inferior portion. Rarely, a hybrid cyst that includes two or more components of a cystic lesion arising from the pilosebaceous unit can develop. The pathogenesis of this unusual disease is not yet known. We report a case of a follicular hybrid cyst which showed combined histologic features of both an epidermal cyst and pilomatricoma, and discuss the possible pathomechanism of the development of this hybrid cyst with a review of the literature.