Cutaneous Keratocyst

 Gorlin-Goltz syndrome: Multiple cutaneous basal cell carcinomas, odontogenic keratocysts of jaw, palmar and plantar pits, rare medulloblastomas, and skeletal abnormalities



• Rare cases not associated with NBCCS also reported




Clinical Issues




• Extremely rare lesions

• Typically occur on head and neck region but can occur at other sites

• Dermal cysts, usually multiple lesions, but may be single


Microscopic




• Dermal-based cystic proliferation lined by 2-5 cell layers of bland squamous cells

• Typically shows corrugated eosinophilic lining (cuticle) and parakeratosis on luminal surface

• No evidence of follicular or sebaceous differentiation (unlike steatocystoma)


Top Differential Diagnoses




• Steatocystoma

• Epidermoid (epidermal inclusion) cyst

• Pilar (tricholemmal) cyst

• Vellus hair cyst

• Hidrocystoma


Diagnostic Checklist




• Bland squamous-lined cyst, which typically shows prominent corrugated eosinophilic lining (cuticle)

image
Scanning Magnification of Cutaneous Keratocyst
Scanning magnification view of a cutaneous keratocyst shows an undulating squamous epithelium lining the irregularly shaped cystic spaces. There are no associated sebaceous glands, unlike steatocystoma.


image
Intermediate Magnification of Cutaneous Keratocyst
The cyst shows a bland, multilayered squamous lining surrounding an irregularly shaped cystic space.

image
High Magnification of Dense Eosinophilic Cuticle of Keratocyst
High-magnification view of the lining of the cyst shows a bland, multilayered squamous epithelium with a dense eosinophilic cuticle image and parakeratosis lining the cystic space.

image
Dense Eosinophilic Cuticle of Keratocyst
Another high magnification of a cutaneous keratocyst shows a bland squamous epithelium with a dense eosinophilic, jagged-appearing cuticle image lining the cystic space.


TERMINOLOGY


Synonyms




• Nevoid basal cell carcinoma syndrome (NBCCS)/Gorlin-Goltz syndrome-associated cutaneous cyst


Definitions




• Rare cutaneous cyst showing features identical to oral keratocysts, often associated with NBCCS


ETIOLOGY/PATHOGENESIS


Genetic




• Most cases are associated with NBCCS (Gorlin-Goltz syndrome: Multiple cutaneous basal cell carcinomas, odontogenic keratocysts of jaw, palmar and plantar pits, rare medulloblastomas, and skeletal abnormalities)
image Mutations for NBCCS in PTCH1 gene on chromosome 9q22.3-q31, which encodes receptor for the Sonic Hedgehog signaling pathway

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Apr 24, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Cutaneous Keratocyst

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