endoscopic submucosal dissection ( esd ) is a standard treatment for early gastric cancer ( egc ) that does not have any risk of lymph node or distant metastases .
the indication for esd is determined by the lesion size , shape , ulceration , depth of invasion , and histologic differentiation . here
, we report a case of egc that resembled a diverticulum , which made it difficult to estimate the lesion size , shape , ulceration , and depth of invasion .
this lesion was treated with esd , which revealed type i+iic egc confined to the submucosal layer , shaped like a false diverticulum because of submucosal inflammation and infiltration .
a 47-year - old korean man visited our hospital for periodic health examination in october 2014 .
he had a history of immunoglobulin g nephropathy , and had undergone bilateral kidney transplantation 15 years ago .
he had an intraductal papillary mucinous neoplasm of the pancreas , and underwent a distal pancreatectomy and splenectomy in october 2012 .
we performed an esophagogastroduodenoscopy ( egd ) , endoscopic ultrasound ( eus ) , and abdomen - pelvis computed tomography ( ct ) .
the egc was shaped like an elevated nodular mucosal lesion with a central inverted area .
the operation history may have contributed to the shape and the inverted type of the central depressed lesion , such as a false diverticulum .
the egc was 15 mm in size and classified as type i+iic according to the japanese classification .
endoscopic forceps biopsy was performed three times at the anterior wall , two times at the posterior wall , and three times at the center opening of the main lesion .
the eus showed that the main lesion was mostly located in the mucosal layer ; however , partial submucosal invasion was observed , and there was no regional lymph node enlargement ( fig .
because of his prior surgery , he needed a total gastrectomy although the lesion was located on the antrum .
for this reason , although the exact character of the lesion was uncertain , esd was done to resect the egc . for the esd technique , we used a gif - q260j instrument ( olympus optical co. ltd . , tokyo , japan ) .
the lesion was raised by means of a submucosal injection of a 37 ml mixture of indigo carmine , epinephrine , and hypertonic saline ( 1:100,000 ) .
although it was difficult to differentiate between true and false diverticulum in this lesion , lifting of the lesion with indigo carmine and epinephrine mixed in saline would suggest that the lesion is a false diverticulum induced by inflammation or the previous operation .
after the injection of indigo carmine solution , the submucosal layer appeared grossly as a white web - like structure ( fig .
in addition , full submucosal dissection was done by using an insulation - tipped ( it ) knife and a hook knife , with a coagulation current of 60 w ( fig .
the en bloc resected tumor was 5.64.7 cm in size and had a central opening with nodular submucosal exposure ( fig .
the safety margin was 0.9 cm of the proximal part , 0.15 cm of the distal part , 1.0 cm of the anterior wall , 0.4 cm of the posterior wall , and 150 m of the basal part .
type i+iic egc coexisted with the false diverticulum , and the pathologic tumor size was 3.61.8 cm , which was larger than the extended criteria for esd ( fig .
the cancer was a tubular adenocarcinoma , intestinal type , based on the lauren classification , and was moderately differentiated .
invasion of the submucosa ( pt1b , depth of submucosal invasion : 450 m ) was observed ( fig .
he had no specific complications and was discharged from the hospital after 4 days . on the basis of the pathologic report , additional surgery was needed ; however , he wanted to undergo follow - up care instead of surgery .
esd was developed for the complete removal of egc in the late 1990s , by using a scope with endoscopic knives . in 2007 , gotoda   proposed the extended esd criteria for egd .
the extended esd criteria were compatible with surgical resection for egc in terms of safety , efficacy , risk of recurrence , and complications .
the definition of gastric diverticulum was suggested in 1661 by moebius in rare cases of gastric wall transformation .
recent articles have commented that the best diagnostic tool for detecting a gastric diverticulum is upper gastrointestinal contrast radiography or egd .
first , true ( congenital ) diverticulum is relatively common , and comprises 70% to 75% of all gastric diverticulum cases .
they are usually located on the posterior wall of the cardiac region . on the 20th and 50th days of gestation
, the stomach is transformed from a fusiform swelling of the foregut into its adult form , during which a 90 rotation of the stomach occurs , including the duodenum , pancreas , and dorsal mesentery .
second , conversely , false ( acquired ) diverticulum consists of partial layers of the stomach .
this type occurs as a result of secondary conditions such as a malignancy , peptic ulcer disease , pancreatitis , or prior surgery .
the false type is most common in adults and is usually located near the gastric antrum .
false diverticula are subdivided into the following groups : ( 1 ) the pulsation type , which may arise from conditions associated with increased intraluminal pressure or impaired gastric wall by gastric ulcer or gastric cancer or surgery , or ( 2 ) the traction type , which can develop owing to perigastric adhesions and can result from inflammatory lesions of the spleen , gallbladder , pancreas , liver , or peritoneum , or from stomach surgery . until recently ,
surgical management is considered only when medical treatment is refractory or symptomatic , the tumor is large , and complications such as bleeding or perforation are observed . since the first successful laparoscopic resection was done for the treatment of a gastric diverticulum in the late 1990s , the safety and feasibility of laparoscopic resection
however , no studies have reported successful treatment of egc with the endoscopic approach in false gastric diverticulum cases . until now , the relation between gastric diverticulum and gastric cancer has not been clearly defined .
the egc was type i+iic , shaped with a central depressed area , and resembled a gastric diverticulum .
precise evaluation of the egc was impossible in the endoscopic examination because of the lack of mucosa , inflammation , and submucosal infiltration . also , the comorbidity of the patient and the risk due to the previous surgery indicated that an endoscopic approach was needed .
therefore , esd was done to resect the false gastric diverticulum that coexisted with the egc .
the main lesion had an invaded submucosal layer ( sm1 ) in the endoscopic examination .
for the procedure , marking with argon plasma coagulation was performed first , as usual ; then , most of the lesion was dissected with an it knife . for the dissection of a lesion with a diverticular shape , the submucosal layer should be definitively identified and careful dissection is pertinent .
for this reason , a hook knife was used to dissect the central area where the fibrosis seemed to be severe in this case . compared with an it knife , dual - type and hook type knives are favored for dissecting fibrotic areas within a narrow field of view . after 3 months , follow - up egd and five endoscopic forceps biopsies for the post - esd scar lesion were performed .
esd has been established as a standard treatment option for egc with an absolute or extended indication .
however , endoscopists are generally reluctant about performing the endoscopic maneuver for egc with an unusual or difficult - to - resect shape .
this is the first report to demonstrate the application of endoscopic resection to an unusually shaped , inverted - type , egc - forming false gastric diverticulum , and its successful treatment with esd .
 endoscopic submucosal dissection ( esd ) is a standard treatment for early gastric cancer ( egc ) that does not have any risk of lymph node or distant metastases . here 
 , we report a case of egc resembling a diverticulum . 
 diverticular formation makes it difficult for endoscopists to determine the depth of invasion and to subsequently perform esd . because the false diverticulum does not have a muscular layer , this lesion can be treated with esd . 
 our case was successfully treated with esd . 
 after esd , the egc was confined to the submucosal layer without vertical and lateral margin involvement . 
 this is the first case in which esd was successfully performed for a case of egc that coexisted with a false gastric diverticulum . 
 an additional , larger study is needed to determine the efficacy of esd in various types of egc , such as a false gastric diverticulum . 
INTRODUCTION
CASE REPORT
DISCUSSION