Imperforate Anus With Perineal Fistula in an Infant Presenting With Constipation and Abscesses: A Case Report.

Chronic constipation and failure to thrive in infants can sometimes mask underlying congenital anorectal malformations. Here, we present a female infant who initially presented with refractory constipation, slow weight gain, and intermittent vomiting, later found to have an imperforate anus with a perineal fistula. Her course was complicated by recurrent fecal impactions, perianal and gluteal abscesses, and repeated hospitalizations. Multiple interventions were required, including manual disimpactions, rectal dilations, full-thickness biopsies, a colostomy with mucus fistula creation, a posterior sagittal anorectoplasty (PSARP), anal Botox-assisted dilations, and an eventual colostomy takedown. Her structural anorectal abnormality led to chronic stool retention, creating a nidus for bacterial overgrowth and tissue breakdown, which explained the recurrent perianal abscesses. Despite early feeding difficulties, recurrent impactions, and postoperative challenges, by age three, she achieved near-complete bowel continence, age-appropriate growth, and developmental milestones. This case illustrates the complexity of managing anorectal malformations and emphasizes the importance of staged interventions, multidisciplinary care, and structured bowel regimens in achieving long-term functional outcomes.