A 62-year-old man was referred to our hospital for treatment of an esophageal cancer
overlying a submucosal tumor (SMT). The SMT was present in the middle thoracic esophagus,
and endoscopic ultrasonography (EUS) demonstrated a hypoechoic tumor with calcification
inside, originating from muscularis propria. We diagnosed it as a benign tumor, such
as a leiomyoma, and it underwent no change in size or form after 8 years of follow-up. The
cancer however was superficial, and magnifying endoscopy combined with narrow-band
imaging (NBI) revealed tortuous B1 vessels with irregular diameters and shapes. The
biopsy specimen revealed squamous cell carcinoma, and endoscopic submucosal dissection
(ESD) was therefore performed ([Fig. 1]).
Fig. 1 Imaging of the superficial esophageal tumor and submucosal tumor: a on endoscopy, showing the lesions in the middle thoracic esophagus; b on magnifying endoscopy combined with narrow-band imaging (NBI), showing loop-like
abnormal vessels with dilation, and irregular diameters and shapes in the intraepithelial
carcinoma; c non-staining of the tumor with iodine; d on endoscopic ultrasonography, showing a hypoechoic lesion of 15 mm in diameter originating
from the muscularis propria.
At first, we attempted to make an incision in the oral and anal sides using a DualKnife
and then to add the circumferences using an IT knife nano. However, fluent endoscopic
maneuverability in proximity to the SMT was difficult because the endoscope came into
contact with the SMT, particularly during the incision on the anal side, which passed
across the SMT and in a valley between the SMT and normal mucosa. Therefore, we used
an SB Knife Jr for the incision and submucosal dissection of these sites. The SB Knife
Jr is a scissor-type knife, which is available for dissection with a fixing endoscope,
thereby preventing inadvertent injury to the muscular layer and promoting safe ESD
[1]. Furthermore, we employed a clip-with-line method to dissect effectively. We achieved
successful ESD of the overlying cancerous mucosa alone, without any complications
in a procedure lasting 100 minutes ([Fig. 2]; [Video 1]).
Fig. 2 Pathology of the resected specimen showing: a a mixed lesion, which was found to be a 20-mm squamous cell carcinoma with an area
of squamous epithelial neoplasia; b, c (on section 4 stained with hematoxylin and eosin [H&E]) that the invasion depth was
to the lamina propria mucosa and there was no lymphovascular involvement with a negative
cut end.
Video 1 Video showing successful endoscopic submucosal dissection of an esophageal cancer
overlying a submucosal tumor that was originating from the muscularis propria using
the SB Knife Jr and a traction-assisted strategy.
This is the first case report of a cancer overlying an SMT originating from muscularis
propria that was successfully treated by curative ESD [2]
[3]
[4]. Based on our experience, we emphasize the importance of EUS to define the layer
from which the SMT originates and the use of NBI magnifying endoscopy to diagnose
invasion depth, followed by determination of an adequate endoscopic resection strategy.
In addition, an SB Knife and traction-assisted strategy were efficient and effective
for safe endoscopic treatment.
Endoscopy_UCTN_Code_TTT_1AO_2AG
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