Skin - Nonmelanocytic tumors
Adnexal tumors-hair follicles
Reviewer: Christopher Hale, M.D. (see Reviewers page)
Revised: 11 June 2014, last major update June 2012
Copyright: (c) 2001-2014, PathologyOutlines.com, Inc.
● Most probably arise from infundibular portion of hair follicles
● Clinically called (incorrectly) sebaceous cyst
● Lesions of palm, sole or other sites may contain HPV 57 or 60
● Cysts contain keratin and lipid debris from sebaceous secretions
● Cysts may be painful if ruptured
Epidermal (epidermoid) type
● Also called infundibular cyst
● Lined by keratinized epithelium with distinct granular layer, contain lamellated keratin but no calcification
● May have seborrheic keratosis-like changes in cyst wall
● 53 year old man with chest wall "sebaceous cyst" (Case of the Week #315)
Follicular cyst (infundibular type)
Case of the Week #315:
Trichilemmal (pilar) type
● Also called isthmus-catagen cyst or a “wen”
● Often on scalp, has trichilemmal-type keratinization (sudden keratinization without a granular layer), uneven boundary between keratinized and non-keratinized cells
● Non-lamellated keratin within the cyst, often with nucleated cells, often calcified
End of Skin - Nonmelanocytic tumors > Adnexal tumors-hair follicles > Keratinous cyst
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