[ Monash University ]

Museum of Pathology

EPIDERMAL CYST

EPIDERMAL CYST

Clinical History

This cystic lesion was removed from the neck of a man aged 69 years.

Pathology

The specimen shows an encapsulated dermal cyst containing gelatinous pale brown material and several smaller white areas. The white patches are due to focal calcification. Histological examination showed the features of an epidermal cyst, i.e. a cystic lesion lined by stratified squamous epithelium with a granular layer and a cyst lumen filled with keratinized squames and debris.

Note

Clinicians sometimes refer to this lesion as a "sebaceous cyst", which is a misnomer as the cyst does not contain sebum. Epidermal cyst is an inclusion cyst probably resulting from minor trauma. It arises either from the surface epithelium or the shaft of a hair follicle. In contrast, a dermoid cyst is a congenital lesion with skin appendages in the wall of the cyst.