Congenital perineal and perianal lipoma with and without anorectal malformation. A case series of eleven patients and updated literature review.

[INTRODUCTION] Perineal and perianal lipomas with and without anorectal malformations (ARM) are rare.

[METHODS] This retrospective study evaluated records from patients with congenital perianal and perineal fatty-tissue growths with and without anorectal abnormalities in two tertiary centres. To contextualize the findings, an updated review of the literature spanning 2019 to 2023 was conducted.

[RESULTS] Eleven patients (m:f = 4:7) from two tertiary care centres were included over eight years; five (m:f = 2:3) had concomitant ARM. Other malformations included heterotaxy syndrome and urogenital malformations. Preoperative MRI was essential for diagnosis and surgical planning. Complete excision was performed in all cases (0-12 months of age) with only one minor wound infection and no recurrence of the lipoma. A posterior sagittal anorectoplasty was performed in cases of concurrent anorectal malformation. Malignancy was ruled out histopathologically in all cases. Postoperative bowel control seems to correlate with the severity of concurrent anorectal or spinal malformation: There was no postoperative fecal incontinence in patients without anorectal malformation.

[CONCLUSION] Perineal and perianal lipomas are rare congenital anomalies that can occur in isolation or in combination with ARM. Preoperative imaging, particularly high-resolution pelvic MRI, is essential for accurate diagnosis and optimal surgical planning. Surgical excision is both safe and curative, even when performed alongside corrective procedures for ARM. Perineal or perianal lipomas do not influence postoperative functional outcome; postoperative continence is primarily determined by the severity of associated anomalies, such as ARM or spinal malformations. The familial cases in our series suggest a potential genetic component, highlighting the need for further research into the underlying embryological and genetic mechanisms.