A pilonidal cyst, called a pilonidal abscess when infected, or a pilonidal sinus or sacrococcygeal fistula when a sinus tract is formed. It is located in or adjacent to the gluteal sacral groove and often contains hair or skin fragments. The term pilonidal means “nest of hair” and is derived from the Latin words pilus and nidus, a term introduced by Herbert Mayo in 1830 and described by R.M. Hodges in 1880 as “pilonidal cyst”. It is usually seen in young people aged 15-24 years and is rare in the umbilicus, axillae and penis, in addition to the sacrococcygeal region. Some patients are asymptomatic. The cause may be ingrown hair, mostly congenital, and is likely to occur in people who sit for long periods of time and sweat a lot. During World War II, more than 8,000 U.S. soldiers were hospitalized for this disease. Also known as “jeep seat or “Jeep riders’ disease”. It is mostly caused by prolonged jeep rides.