Infantile Perianal Pyramidal Protrusion

The mother of a 7-month-old female infant was very concerned about a “bump” in her child’s perianal area that she thought was a hemorrhoid.

On close inspection, the base of the triangular, seemingly asymptomatic lesion (shown here with the infant lying on her belly) was anterior to the anus on the perineal median raphe. The lesion was excised in the office using local anesthesia, and the opening was sutured with 3.0 chromic catgut. The area was cleaned with warm water until it healed several days later.

The pathological diagnosis was infantile perianal pyramidal protrusion. This perianal soft tissue swelling may be mistaken for a skin tag, or acrochordon. Its location may be related to anatomic characteristics of the perineum and median raphe. Microscopically, there is epidermal acanthosis, marked edema, and mild
inflammatory infiltrate. The average age at diagnosis is 14 months, although the time of onset is often uncertain; about 94% of cases involve girls.^1-3

The differential diagnosis includes genital warts, granulomatous lesions of inflammatory bowel disease, and rectal prolapse. Infantile perianal pyramidal protrustion can be a manifestation of lichen sclerosus et atrophicus and may be associated with recurrent urinary tract infections, dysuria or painful defecation,² and regional enteritis.^4,5 Similar to other manifestations of lichen scelerosus et atrophicus, infantile perianal pyramidal protrustion may be misinterpreted as a sign of sexual abuse.

Spontaneous regression of the lesion is common. Treatment options include observation, simple surgical excision, or destruction by electrodesiccation or cryotherapy. Reassurance to relieve parental anxiety that the condition is benign and treatable is an important part of therapy.