The rectum is the ideal part of the large bowel in which to perform deep excision
for dysplastic lesions [11]
[22]. However, in cases of severe submucosal fibrosis and deep invasion of a carcinoma
into the submucosa, performing endoscopic submucosal dissection can be very difficult.
The intermuscular plane of dissection and myectomy of the inner muscular layer (endoscopic
intermuscular dissection) previously have been described for treatment rectal neoplastic
lesions, overcoming the compactness of the submucosa layer [33]
[44]
[55].
An 85-year-old man was referred to our department for a flat, 15-mm, dysplastic lesion
(high-grade dysplasia [HGD]) close to the dentate line ([Fig. 1Fig. 1]). Morphologically, the polyp was a Paris Classification 0-IIa, NICE Classification:
2 and LST-Classification: NG-Type/Flat elevated. The patient had completed radiotherapy
for prostate cancer 14 months before our evaluation and was treated with mesalamine
enemas. The surrounding rectal mucosa was scarred and compact with white stripes and
telangiectasias as a secondary effect of radiation. We decided to perform a deeper
excision into the intermuscular plane to avoid the severely fibrotic submucosal plane
([Fig. 2Fig. 2], [Fig. 3Fig. 3], [Fig. 4Fig. 4] and [Video 1Video 1]). A single dose of broad-spectrum antibiotics was given interprocedurally to the
patient. The defect remained open after the excision without any adverse events, such
as bleeding, fever or pain, and the patient was discharged the next day ([Fig. 5Fig. 5]). The pathology report revealed tubular adenoma with HGD radically resected. Follow-up
endoscopy in 6 months later revealed almost complete healing of the defect ([Fig. 6Fig. 6]).
Fig. 1
Fig. 1 A 15-mm flat polyp in the area affected by radiation proctitis.
Fig. 2
Fig. 2 Inability to lift the compact and fibrotic submucosal space by fluid injection.
Fig. 3
Fig. 3 Fluid injection into the intermuscular space.
Fig. 4
Fig. 4 Dissection between the inner (circular) and outer (longitudinal) muscle layers.
Fig. 5
Fig. 5 Open defect after removal of the dysplastic rectal lesion.
Fig. 6
Fig. 6 Healing of the dissection on follow-up endoscopy (6 months).
Endoscopic intermuscular dissection (EID) of a dysplastic severely fibrotic benign
rectal lesion.Video 1Video 1
The dissection was performed between the inner circular and outer longitudinal muscles,
instead of between the submucosal and muscle layers. The myectomy was achieved by
using a Hook Knife (Olympus, Tokyo, Japan). Resecting benign severely fibrotic lesions
in the rectum may constitute one of the advantages of EID, except in the case of resection
of deeply infiltrative rectal carcinomas [55].
Video steps
HGD in the area affected by radiation proctitis
Starting mucosal incision without adequate lifting due to fibrosis
Compact and fibrotic submucosal space
Changing knife for myotomy
Entering intermuscular space
Injection to expand the tiny intermuscular space
Cautious intermuscular dissection
After completing circumferential incision, continuing with dissection
