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Dermal cysts: Diagnostic featuresDermal cysts: Diagnostic features

Deba P Sarma, MDOmaha

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Ep idermal cystEp idermal cyst

Dermal cyst lined by e p idermis with granular layer and containing

flakey keratin.

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Pilar cyst ( Trichilemmal cyst)Pilar cyst ( Trichilemmal cyst)

Dermal cyst lined by less baso p hilic trichilemmal e p ithelium containigcom p act p ilar ty p e keratin. Calcification is common.

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Infundibular cyst (Pilar cyst, infundibular ty p e)Infundibular cyst (Pilar cyst, infundibular ty p e)

Pilar cyst close to the e p idermis arising from the infundibulum of thehair. Lined by trichilemmal (LT) as well as e p idermal e p ithelium withgranular layer (RT). Content of the cyst: Com p act keratin.

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Ep idermal and p ilar cystEp idermal and p ilar cyst

Com p are the e p idermalcyst with normal e p idermis.Com p are the p ilar cyst withnormal hair.

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Dermoid cystDermoid cyst

Dermal cyst lined by e p idermis with all normal adnexal structures.

Lumen contains flakey keratin and hair .

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Ep idermal, p ilar, dermoid cyst com p aredEp idermal, p ilar, dermoid cyst com p ared

Ep idermal cyst:1. Lining: Normal e p idermis

with granular layer. Noadnexal structure.

2. Content: Flakey keratin.

Pilar cyst:1.Lining: Paletrichilemmal e p ithelium,no granular layer.2.Content: Com p actkeratin

Dermoid cyst:1. Lining: Ep idermis with

adnexae.2. Content: Flakey keratin,

hair.

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Ru p tured e p idermal cystRu p tured e p idermal cyst

D

Dermal cyst lined by giant cells, histiocytes,sometimes residuale p idermis containing flakey keratin within the cyst cavity.

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H idrocystomaH idrocystoma

Dermal cyst lined by small cuboidal cells of sweat duct. Cystcavity contains fluid ( sweat ), but no keratin.

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SteatocystomaSteatocystoma

Multilocular dermal cyst lined by wavy squamous e p ithelium withsebaceous glands. Cyst cavity contains oily fluid, but no keratin.Origin of this cyst is the sebaceous gland duct.

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