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)

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.

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

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 and parakeratosis lining the cystic space.

Dense Eosinophilic Cuticle of Keratocyst
Another high magnification of a cutaneous keratocyst shows a bland squamous epithelium with a dense eosinophilic, jagged-appearing cuticle 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)