P0175 - Retrorectal Cystic Hamartoma: A Rare Cause of Constipation

Micaella Kantor, MD¹, Sarah Arvaneh, DO², Humberto J. Rios, MD³, Luis Geada, MD⁴, Juan Sarol, MD², Luis Nasiff, MD, FACG^1
1Larkin Community Hospital, Miami, FL; ²Larkin Community Hospital, Hialeah, FL; ³Larkin Community Hospital Palm Springs, Hialeah, FL; ⁴Kendall Regional Medical Center, Miami, FL

Introduction: Retrorectal cystic hamartomas, or tailgut cysts, are rare congenital malformations which develop almost exclusively in the presacral space. These lesions arise postnatally from primitive gut remnants that have failed to regress during gestation. The overall incidence is estimated 1 in 40,000, with a strong female to male predominance of 5:1. These cysts may present as an incidental finding on imaging, or with a myriad of symptoms due to mass effect, such as abdominal pain, rectal bleeding, constipation, urinary and neurologic symptoms. Given the rarity of these lesions and variable clinical presentation, diagnosis may often be missed. We present a case of a young man with constipation.

Case Description/Methods: A 34-year-old healthy male presented with abdominal pain, nausea and worsening constipation for 4 days. He has suffered from chronic constipation, however, has been worsening for the past year. CT Abdomen showed a large thin-walled non-enhancing fluid filled cystic structure, measuring 9.9 x 14.4 x 17.7 cm, nearly completely filling the pelvis and extending to the right peri-rectal region, displacing and compressing the sigmoid colon (Figure 1). MRI Pelvis with IV contrast revealed a proteinaceous fluid collection extending from the lower right peri-rectal region into the abdomen with regional mass effect upon the adjacent pelvic structures. Digital rectal exam revealed a smooth firm mass, extrinsically along the left anal canal/rectum. Colonoscopy showed extrinsic severe stenosis measuring 20 cm long, along the rectum and distal sigmoid colon. Patient was referred for colorectal surgery.

Discussion: The presacral space is surrounded by the rectum anteriorly, sacrum and coccyx posteriorly and peritoneal reflection superiorly. Various presacral cysts may form in this space based on the embryogenic cell of origin. Definitive diagnosis of the cyst depends on histopathologic findings. Tailgut cysts tend to be a well-circumscribed, soft, multiloculated cystic mass filled with mucoid material. The cysts can be lined by various epithelial cells. Malignancy arising from the epithelial lining of the cyst has been reported. MRI is the cornerstone for diagnosis and preoperative planning. Preoperative biopsy of the tumor under endoscopic guidance is generally not recommended as this may lead to complications and make complete surgical excision difficult. Complete surgical excision is the treatment, preventing complications such as infection, recurrence, and malignant transformation.



Disclosures:


Micaella Kantor, MD¹, Sarah Arvaneh, DO², Humberto J. Rios, MD³, Luis Geada, MD⁴, Juan Sarol, MD², Luis Nasiff, MD, FACG¹. P0175 - Retrorectal Cystic Hamartoma: A Rare Cause of Constipation, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.