“Scoping-around” a sigmoidorectal intussusception: a pitfall of flexible sigmoidoscopy

Abstract

A 66-year-old woman presented with 3-month history of progressive constipation and occasional bright red per-rectal bleeding. An urgent flexible sigmoidoscopy (FS) showed an abnormal lesion within the anal canal and biopsy showed tubulovillous adenoma with low-grade dysplasia. She mentioned “no” response to a preparatory enema given before FS. The patient presented 4 days after FS with absolute constipation and passing a “jelly-like” substance since the procedure. A large soft tissue lump with “currant jelly” mucus discharge was noted on per-rectal examination. An abdominal x ray was suggestive of distal large bowel obstruction and a water-soluble contrast enema suggested sigmoidorectal intussusception. The intussusception was irreducible with rigid sigmoidocopy and therefore the patient underwent sigmoid resection and Hartmann’s procedure, which showed a distal sigmoid polyp as a lead point for the intussusception. Retrospectively looking into the case, the intussusception was present during FS, but was scoped-around and therefore lesion was considered to be in the anal canal.

BACKGROUND

The aims of this report are: (1) to present what is thought to be the first reported scenario of “scoping-around” an intussusception, and thereby create awareness among endoscopists (scoping-around basically means traversing the space between the intussusceptum and intussuscipiens); (2) to present the symptoms and signs of presentation of this rare entity of sigmoidorectal intussusception and thereby allow timely diagnosis of such cases in future; (3) to show the classic finding of sigmoidorectal intussusception on a water-soluble contrast enema, thereby necessitating the importance of this investigation in such cases.

CASE PRESENTATION

A 66-year-old was referred with 3-month history of progressive constipation and occasional bright red per-rectal bleeding. An urgent flexible sigmoidoscopy (FS) showed an abnormal lesion within the anal canal, and biopsy showed tubulovillous adenoma with low-grade dysplasia. She mentioned “no” response to preparatory enema given before FS. The patient presented 4 days after FS with absolute constipation and passing a “jelly-like” substance since the procedure. On digital rectal examination a large soft tissue lump with pinkish “currant jelly” mucus discharge was noted. She had been diagnosed with small cell left lung cancer a month previously. She smoked 20 cigarettes per day and took alcohol occasionally. There was no family history of bowel or other malignancy.

INVESTIGATIONS

FS showed an abnormal lesion within the anal canal, and this was biopsied (fig 1). The scope was reported to have reached the proximal sigmoid colon, but it had actually traversed the space between the intussusceptum and intussuscipiens. Abdominal x ray was suggestive of distal large bowel obstruction. Water-soluble contrast enema passed only as far as the distal sigmoid colon and showed the classic appearance of sigmoidorectal intussusception (figs 2 and 3).

Figure 1.

Flexible sigmoidoscopy showing an abnormal lesion of the anal canal. The lesion was a tubulovillous adenoma of the sigmoid colon.

Figure 2.

Water-soluble contrast enema showing the classic appearance of “sigmoidorectal intussusception” with the proximal bowel loop telescoping into the distal loop.

Figure 3.

Water-soluble contrast enema: sigmoidorectal intussusception causing large bowel obstruction.

DIFFERENTIAL DIAGNOSIS

The two common differentials were rectal prolapse and anal canal or rectal polypoidal lesion.

TREATMENT

The intussusception was irreducible with a trial of rigid sigmoidocopy and therefore the patient underwent sigmoid resection and Hartmann’s procedure, which showed distal sigmoid polyp as a lead point for the intussusception. As the patient was awaiting chemotherapy for her lung cancer, it was decided against primary anastomoses. Retrospectively looking back into the case, the intussusception was present during flexible sigmoidoscopy, but was scoped-around and therefore lesion was considered to be in the anal canal.

OUTCOME AND FOLLOW-UP

The histology of resected sigmoid confirmed tubulovillous adenoma with features such as extensive vascular congestion, confirming intussusception. The patient recovered quite well from her procedure and started chemotherapy for lung cancer 7 days after the Hartmann’s procedure.

DISCUSSION

To our knowledge, scoping-around an intussusception has not been reported in the literature. This basically means traversing the space between the intussusceptum and intussuscipiens, thereby identifying the intussusceptum as an intraluminal pathology. FS is routinely used as an initial investigation of choice for lower gastrointestinal (GI) pathology and is a safe and effective procedure in skilled hands.¹ There has never been a doubt regarding the usefulness of FS, apart from concerns with “incomplete depth of insertion” that may miss cancerous lesions.² Retroflexion of the endoscope during FS should be routinely performed, as this has shown to increase the detection of neoplastic lesion³ and could have helped diagnosis in our patient.

Sigmoidorectal intussusception is a very rare condition, with fewer than 15 cases mentioned in the literature to date. The intussusception is usually secondary to a lead point such as a sigmoid lipoma,⁴ a benign or sigmoid lesion⁵ or a rectal lesion.⁶ The peristalsis of the proximal bowel with ingested food pushes the lead point with the adjacent bowel into the relaxed intestinal segment distal to it. Because of its rare incidence and non-specific symptoms and signs, precise preoperative diagnosis is made in less than half of the cases.⁷ Early diagnosis is essential, as any delay can lead to ischaemia of the intussuscepted bowel and a poor prognosis.

Water-soluble contrast enema can show the characteristic finding of a cup-shaped, contrast-filled cavity with bowel loop floating within, and CT can give additional preoperative information including the possible extension and/or dissemination of a malignant tumour.⁸

The contrast enema failed to reduce our patient’s intussusception because of adhesions between the layers of the bowel; this is possible in a delayed presentation. The intussusception can be given a trial of reduction with sigmoidoscope or sponge-on-stick,⁵ and the definitive surgical resection can be carried out for the intestinal segment with lead point.^4,5

LEARNING POINTS

• Sigmoidorectal intussusception is a rare entity, and history of absolute constipation, “currant-jelly-like” per-rectal (PR) discharge and prolapsing PR mass should raise suspicion.

• Endoscopists need to be aware of the concept of “scoping-around” an intussusception, thereby avoiding delay in diagnosis and preventing bowel ischaemia.

• Rectal retroflexion during endoscopy has shown to add additional information regarding anal and rectal lesions, and therefore should be routinely performed.

• Water-soluble contrast enema is the investigation of choice to identify intussusception, but CT is warranted to delineate the extent of the accompanying lesion.