ABSTRACT
A hybrid cyst is a rare condition which includes any type of cyst arising from the various parts of the pilosebaceous unit. We report a case of hybrid cyst with infundibular, isthmic, and pilomatrical differentiation. A 12-year-old boy presented with a mass on the right cheek. The physical examination revealed an oval-shaped, dark-gray protruding mass with dimensions of 0.9 cm × 0.6 cm that was non-tender to palpation. The mass was totally excised. The diagnosis of a hybrid cyst was confirmed by histological evaluation. It was a well-encapsulated mass and showed combined histologic features of infundibular, isthmus, and pilomatrical differentiation. The hybrid cyst is a follicular cyst that includes two or more components of a cystic lesion arising from the pilosebaceous unit. Occasionally, there have been reports of hybrid cysts consisting of two components in differentiation, but those showing more than two components of differentiation have been extremely rare. The pathogenesis of this unusual disease is not yet known.
Subject(s)
Cheek , Child , Epidermal Cyst/diagnosis , Epidermal Cyst/surgery , Follicular Cyst/diagnosis , Follicular Cyst/surgery , Humans , Male , Pilomatrixoma/diagnosis , Pilomatrixoma/surgeryABSTRACT
Pilomatricoma is a benign tumor derived from the hair matrix. Pilomatricoma-like changes have been described in epidermal cysts in Gardner's syndrome. Apart from this association, a cyst can arise from various portions of a hair follicle, and combine to form a hybrid cyst. Follicular hybrid cyst is an interesting pathologic phenomenon, and needs to be explained for their pathogenesis. We present a case in which a pilomatricoma was situated in the immediate vicinity of an epidermal cyst. Histopathologic findings showed that one part of the cyst had a feature of an epidermal cyst, and the other part had a feature of a pilomatricoma.
Subject(s)
Chimera , Epidermal Cyst , Gardner Syndrome , Hair , Hair Follicle , PilomatrixomaABSTRACT
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.
Subject(s)
Epidermal Cyst , Hair , PilomatrixomaABSTRACT
It is known that different parts of a pilosebaceous unit, namely the infundibulum, isthmus, sebaceous ducts, and bulbar or inferior portion, can give rise to a variety of cutaneous cysts, such as epidermal, trichilemmal, steatocystoma, or pilomatricoma. In rare instances, a cyst can arise from various portions of a hair follicle and combine to form a hybrid cyst. The pathogenesis of this lesion is uncertain. Studying the clinicopathological features of hybrid cysts helps us to understand the pathogenesis of disease which can arise from pilosebaceous units. Epidermal cysts and pilomatricoma are recognised to be clinically similar but histologically distinct entities. We present a case of a patient with a solitary nodule on the posterior neck, showing combined histologic features of both an epidermal cyst and pilomatricoma.
Subject(s)
Humans , Epidermal Cyst , Hair Follicle , Neck , PilomatrixomaABSTRACT
Both eruptive vellus hair cyst and steatocystoma multiplex are uncommon conditions. There are clinical similarities between these two entities, but histological features are distinctive. We describe a patient with multiple subcutaneous nodules on the chest and both axilla, showing combined histological features of both an eruptive vellus hair cyst and steatocystoma multiplex. This case suggests that eruptive vellus hair cyst and steatocystoma multiplex are variants of one disorder which originate in the pilosebaceous duct.