Case of the Month

A mother brings her 10 month-old child in for a follow up visit of atopic eczema. She also wants to know about a strange bump or skin tag that developed near the child’s anus over the past week or so, that she noticed during diaper changes. In addition to eczema, the baby has been significantly constipated the past 2 weeks.

Diagnosis: Infantile Perianal Pyramidal Protrusion

Infantile perianal pyramidal protrusion typically presents as an asymptomatic pyramidal soft tissue protrusion with a pink, rose red , or purplish red surface, along the midline, usually anterior to the anus, with the major axis consistent with the median raphe(1).

The condition 'Infantile perianal pyramidal protrusion' was first reported in 1996 (1,4). It appears/develops at the midline raphe of the perineum, anterior to the anus. The cause is not completely clear, but most believe that there is a congenital weakness in the midline raphe of the perineum. With the pressure of Valsalva, (associated with constipation), the area weakens and tissue protrudes. Most often, the lesion will resolve spontaneously without complication (or treatment) when the baby's constipation resolves. It is important to recognize these relatively common lesions, so they are not confused with condyloma/child abuse or hemorrhoids. Histologically they are a papular lesion containing a fibrovascular core with inflammatory cells. At higher magnification, epidermal acanthosis and dilated vessels with fibrous tissue infiltrated by lymphocytes are mainly observed (3). Interestingly, most cases have been reported in females. Concerning Infantile perianal pyramidal protrusion, there are multiple variations in shape. The lesions may take on various configurations such as papular, peanut, tongue and cigar. Resultantly, some dermatologist have suggested the condition be called ‘Infantile Perianal Protrusion.’ There are other similar lesions associated with infantile lichen sclerosis, and another variation acquired in adulthood.

For informative discussions of 'infantile perianal pyramidal protrusion,' please see these references:

1. https://www.dermatologyadvisor.com/dermatology/infantile-perianal-pyramidal-protrusions-infantile-perineal-protrusion-infantile-perianal-protrusion/article/691217/
2. https://www.jpeds.com/article/S0022-3476(16)31171-4/fulltext
3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4037693/
4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4462916/
5. https://www.consultant360.com/articles/infantile-perianal-protrusion