A pilonidal cyst
, also referred as sacrococcygeal fistula
, is a cyst
near the natal cleft
of the buttocks that often contains hair and skin debris.
Pilonidal means "nest of hair", and is derived from the Latin words for hair ("pilus") and nest ("nidus"). The term was used by Herbert Mayo
as early as 1830. R.M. Hodges was the first to use the phrase "pilonidal cyst" to describe the condition in 1880.
Pilonidal cysts can be painful, afflict men more frequently than women, and typically occur between the ages of 15 and 24. Although usually found near the tailbone
, the condition can also affect the navel
, though these locations are much more rare.
tract, or small channel, may originate from the source of infection and open to the surface of the skin. Material from the cyst may drain through the pilonidal sinus. A pilonidal cyst is usually painful, but if it is draining, the patient might not feel pain.
One proposed cause of pilonidal cysts is ingrown hair
. Obesity and excessive sitting are thought to predispose people to the condition because they increase pressure on the coccyx
region. Trauma is not believed to cause a pilonidal cyst, however such an event may inflame an existing cyst. However there are cases where this can occur months after a localized injury to the area. Some researchers have proposed that pilonidal cysts may be the result of a congenital pilonidal dimple. Sweating
or excessive sweating can also contribute to the cause of a pilonidal cyst.
The condition was widespread in United States Army during World War II. More than eighty thousand soldiers having the condition required hospitalization. It was termed "Jeep riders' disease," because a large portion of people who were being hospitalized for it rode in jeeps, and prolonged rides in the bumpy vehicles caused the condition due to irritation and pressure on the tailbone.
Treatment may include antibiotic therapy, hot compresses and application of depilatory creams.
In more severe cases, the cyst may need to be lanced or surgically excised (along with pilonidal sinus tracts). Post-surgical wound packing may be necessary, and packing typically must be replaced twice daily for 4 to 8 weeks. In some cases, 1 year may be required for complete granulation to occur. Sometimes the cyst is resolved via surgical marsupialisation.
Surgeons can also excise the sinus and repair with a reconstructive flap technique, which is done under general anesthetic. This approach is mainly used for complicated or recurring pilonidal disease, leaves little scar tissue and flattens the region between the buttocks, reducing the risk of recurrence.
The condition has a 40% chance of recurrence, even after surgery. Recurrence is greater if the surgical wound is sutured in the midline, as opposed to away from the midline, which obliterates the natal cleft and removes the focus of shearing stress.
A pilonidal cyst can resemble a dermoid cyst
, a kind of teratoma
(germ cell tumor
). In particular, a pilonidal cyst in the gluteal cleft
can resemble a sacrococcygeal teratoma
. Correct diagnosis is important because all teratomas
require complete surgical excision, if possible without any spillage, and consultation with an oncologist