Infantile perianal (perineal) pyramidal protrusion.

Infantile perianal (perineal) pyramidal protrusion (IPPP) is a newly described entity with fewer than 100 reported cases. Awareness of this entity is important to avoid an improper inference of sexual abuse or other anogenital disease.

A 9-month-old healthy girl was brought by her mother for dermatologic examination of her perineum complaining of a new lesion that developed three weeks ago. Dermatological examination revealed a 1 cm, solitary, flesh-colored, pyramidal protrusion located in the midline anterior to the anus [Figure 1]. The lesion was not tender on palpation. There was no history of constipation or suspicion of sexual abuse. A pediatric surgery consultation excluded rectal prolapse, hemorrhoids and anal fissure by clinical examination. A clinical diagnosis of IPPP was made. After 6 months, the lesion disappeared without treatment.

Figure 1

Solitary, flesh-colored, pyramidal protrusion located in the midline anterior to the anus

IPPP was firstly described by Kayashima et al. in 1996.[1] It appears as a pyramidal soft tissue protrusion with a smooth surface, covered with rose-colored skin.[2] They are classically located in the midline just anterior to the anus, generally occurring in girls and mostly seen in infants.[23] A constitutional anatomic weakness in the perineum of female patients has been hypothesized as a potential cause.[3] Three types of IPPP were defined, including (i) constitutional (inherited) IPPP, (ii) functional IPPP and (iii) IPPP associated with lichen sclerosus and atrophicus. Constitutional IPPP remains unchanged over the years, while functional IPPP can be associated with constipation or diarrhea and regress with time.[2456] Some IPPP lesions may represent an early manifestation of lichen sclerosus; this could be due to rearrangement of the fibrous tissue caused by the inflammation related to the disease.[25] Histopathology is relatively non-specific and includes acanthosis, upper dermal edema and mild inflammatory infiltrate; vacuolar and lichen sclerosus-like changes may occur in a subgroup of patients.[23]

In the differential diagnosis, other perianal lesions including sexual abuse signs, hemorrhoids, genital warts, sentinel tag of anal fissure, granulomatous lesions of inflammatory bowel disease, perineal midline malformation, rectal prolapse and infantile hemangioma must be considered.[24] The evolution of the lesion is variable, with complete resolution in some cases or residual lesions in others. Preventing constipation or diarrhea may be helpful. Erythema and irritation may be reduced by the application of a topical corticosteriod.[7] Conservative follow-up is sufficient for most patients, as in the present case.

In conclusion, it is important to recognize IPPP to avoid an erroneous investigation for sexual abuse or other perianal disease as the evaluation and examination process can be traumatic both for the patient and for the family.