A case of rectal mucocele post-Hartmann’s procedure

A 78-year-old bedbound female, with a past medical history of Guillain–Barré syndrome, presents with back pain, haematuria, and gel-like anal discharge following Hartmann’s procedure for sigmoid volvulus.

Sagittal and axial computed tomography (CT) images showed a dilated rectal stump filled with a homogenous, low-attenuation fluid collection and dependent hyperdense material representing chunks of dystrophic calcification.

Mucoceles of the digestive system have been encountered in the appendix, gallbladder, oesophagus, and, less frequently, colon and rectum. A rectal mucocele is a mucus-containing collection occurring due to reduced or absent drainage of the secretions of the rectal mucosa via the anal canal. This is often associated with benign or malignant anal stenosis, increased anal sphincter tone, or invagination of the mucosal epithelium during surgical procedures [1,2]. Cases of rectal mucoceles have been described previously as occurring after subtotal [3] or total colectomy [4], haemorrhoidopexy [5], and Hartmann’s procedure [6,7]. In our case, it is likely of multifactorial aetiology due to the preceding Hartmann’s procedure and abnormalities in intestinal motility and sphincter tone due to advanced age and immobilised state.

Distension of the rectum can produce a variety of clinical manifestations due to the compressive effect on surrounding structures [6]. This case demonstrates these pressure effects, on the back causing pain, and on the bladder causing haematuria, which prompts the need for imaging studies. On CT scans, rectal mucoceles appear as well-circumscribed, homogeneous, low-attenuation fluid collections and are more commonly found to be arising from the posterior wall of the rectum [1]. Magnetic resonance imaging (MRI) can aid in the diagnosis and can show characteristic findings of mucin-containing lesions with a hypointense or isointense signal on T1-weighted images and a hyperintense signal on T2-weighted images. A case of rectal mucocele investigated by endoscopic ultrasound (US) has been described in the literature as showing the characteristic “onion-skin” appearance, a common and specific feature for appendiceal mucoceles as seen on transabdominal US [8].

Cytological and histopathological testing can be performed in cases of unclear diagnosis. Several treatment options have been described in the literature, including drainage via a rectal catheter [6], endoscopic US-guided drainage [4], cyst extirpation [1], and proctectomy [2]. This patient was treated with transanal rectal drainage via rectal tube.

In patients with prior colorectal surgery, rectal mucoceles should be considered when visualising cystic lesions in the pelvis. Differentiating this from other potential complications, such as pelvic abscess or anastomotic leak, can guide appropriate management. Additionally, the imaging findings of a rectal mucocele can be easily confused with other postoperative complications, such as abscesses, haematomas, or neoplastic recurrence. This case highlights the importance of accurate interpretation and differential diagnosis in the context of prior colorectal surgery. Early detection of a rectal mucocele can prevent further complications such as infection, abscess formation, or bowel obstruction. This case emphasises the role of imaging in guiding management decisions in complex postoperative patients.

All patient data have been completely anonymised throughout the entire manuscript and related files.