When the term "pilonidal cyst" is used one immediately thinks of the pathologic hair-bearing cysts seen in the vicinity of the midline coccygeal region. The reporting of thousands of these cases in the literature, plus time, has made this anatomic location conventional, and it is difficult to think of a pilonidal cyst occurring in any other site.
In 1943 and 1944 4 cases of pilonidal cyst were seen which were located in the perineum, several inches anterior to the anal verge. These cases were interesting diagnostic problems since they were all sent to the Ano-Rectal Surgical Section of Brooke General Hospital with a diagnosis of "anterior anal fistula." Three patients had what appeared to be external fistulous orifices in the left anterolateral perianal quadrant, and 1 had an orifice located in the right anterolateral perianal quadrant. The orifices were situated from 1 to 3 inches (2.5 to 7.6 cm.) from
SMITH TE. ANTERIOR OR PERINEAL PILONIDAL CYSTS. JAMA. 1948;136(15):973-975. doi:10.1001/jama.1948.02890320017004