Pilonidal Cyst
Synonyms: Pilonidal sinus Pilonidal disease Barber’s interdigital pilonidal sinus (when located in the interdigital spaces)
Pilonidal cysts typically present as an inflamed, painful, cystic swelling in the upper gluteal cleft or sacrococcygeal area, but they have been described in other locations. They most commonly occur in White individuals and in males who are hirsute. Pilonidal cysts usually present clinically during the second decade of life.
The etiology of pilonidal cysts and sinuses has been a controversial issue. Some authors have argued that they are congenital, essentially representing a dermoid cyst, whereas most authors now believe that the vast majority of lesions are acquired, representing a foreign body response to entrapped hair. A pilonidal cyst can be seen as part of the “follicular inclusion tetrad” which consists of acne conglobata, hidradenitis suppurativa, dissecting cellulitis (perifolliculitis capitis abscedens et suffodiens), and pilonidal cyst (see Ch. 38). Persistent exogenous hairs in the interdigital space of barbers or dog groomers may incite an encompassing epidermal proliferation, giving rise to a pilonidal cyst.
Pathology
Histologic features are those of an epidermal-lined cyst or sinus tract. Cyst cavities contain hair and keratin debris and are surrounded by fibrosis, granulation tissue, and mixed inflammation.
Treatment
Treatment is surgical.