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Proliferating Hybrid Follicular Tumor
Author(s) -
Craig E.,
Fung M.
Publication year - 2005
Publication title -
journal of cutaneous pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 75
eISSN - 1600-0560
pISSN - 0303-6987
DOI - 10.1111/j.0303-6987.2005.320bb.x
Subject(s) - epidermoid cyst , vellus hair , pilomatricoma , infundibulum , follicular cyst , apocrine , pathology , cyst , biology , keratin , anatomy , hair follicle , medicine , dermatology , scalp , microbiology and biotechnology
Epithelial cysts are commonly encountered in clinical practice, most usually as epidermoid (infundibular) cysts, and trichilemmal (pilar) cysts. A multitude of other cystic structures can arise from the pilosebaceous unit, including dermoid cyst, pilonidal cyst, eruptive vellus hair cyst, steatocystoma, pilomatricoma, as well as eccrine and apocrine hydrocystoma. Epidermoid cysts are thought to derive from the follicular infundibulum, and express keratin 10 but not keratin 17, whereas trichilemmal cysts are believed to derive from the follicular isthmus, and express both keratins 10 and 17. Proliferating follicular cysts generally exhibit trichilemmal keratinization. In addition to the various aforementioned cysts, hybrid cysts have been reported. The majority of hybrid cysts described have been epidermoid‐trichilemmal, in which the upper portion of the cyst shows epidermoid keratinization with a sharp transition inferiorly to trichilemmal keratinization. However other hybrid variants have been reported, including epidermoid‐pilomatricoma, epidermoid‐apocrine hydrocystoma, trichilemmal‐pilomatricoma, eruptive vellus hair cyst‐steatocystoma, and eruptive vellus hair cyst‐trichilemmal cysts. Here we report, to the best of our knowledge, the first case of a proliferating hybrid cyst containing both epidermoid and trichilemmal components, which presented on the scrotum of a 44‐year‐old man.