Epidermal cysts are the most common of all cysts.

The purpose of this paper is to report the clinical and histopathologic features of epidermal cysts.

We reviewed the clinical and histopathologic features of 205 cases that were diagnosed with epidermal cysts at the department of dermatology in Anam Hospital of Korea University for 11 years, from January 1983 to December 1993.

1. Of the 3,400 cases of skin biopsy specimens, 205 cases were epidermal cysts(6%). There were 141 male cases (68.8%) and 64 female cases (32.2%). The ratio of male to female was 1:0.45.

2. Most patients with epidermal cysts belonged to age ranging from 20 to 59 with the highest incidence in the 3rd decade.

3. The site of predilection of the epidermal cysts were face 94(45.9%), trunk 37(18.0%), neck 23(11.2%), leg 21(10.2%), arm 19(9.3%),scalp 7(3.4%), scrotum 2(1.0%), and vagina 2(1.0%).

4. Histopathologically, 61 cases (29.3%) were ruptured. The most common cystic wall change was acanthosis followed by atrophy, hyperplasia, hypergranulosis, parakeratotis, basalioma-like change, squamous eddies, dyskeratosis. The most common cystic content was keratinous material followed by parakeratotic cells, pigment, bacterial colony, RBC, inflammatory cells, hair shaft, calcification, trichilemmal keratinization, pilomatricoma-like change. The most common stromal change was giant cells followed by fibrosis, granulation tissue formation,vessel proliferation, pigment.

According to our results, which agree with those of Chung, the epidermal cysts occur as a disease particular to young men, especially on the face. Histopathologically, when an epidermal cyst ruptures and the contents of the cyst are released into the dermis, a considerable foreign body reaction with numerous multinucleated giant cells results.