the occurrence of liposarcomas in the gastrointestinal tract is very low and the reported incidence of gastrointestinal liposarcoma is 0.1% to 5.8% at autopsy .
the incidence of liposarcomas occurring at the esophagus is particularly low , where they form only 1.2% to 1.5% of all gastrointestinal lipomas .
the optimal treatment method for primary esophageal liposarcoma has not been established yet , but all reported cases so far have been treated by surgical means .
although the use of therapeutic esophageal intervention has become increasingly common , nonsurgical therapy of primary esophageal liposarcomas has not been described yet in the literature . here ,
we present a case of a large esophageal liposarcoma which was resected by endoscopic submucosal dissection ( esd ) under general anesthesia .
a 44-year - old male patient was admitted to our hospital for 4 months of dysphagia which was exacerbated during the recent weeks . an abdominal computed tomography ( ct ) scan showed a 15 cm long mass protruding into the esophageal lumen on coronal image .
the majority of the tumor showed fat attenuation , internal septa - like structures , and soft tissue density ( fig .
, there was a yellowish , soft , and movable subepithelial tumor ( set ) located 20 to 35 cm away from the upper incisor .
endoscopic ultrasonography showed a nonhomogeneous submucosal mass located in the posterior wall of upper to mid esophagus ( fig .
although the tumor had a stalk , the stalk was too huge to use a snare .
the procedure was done using a cap - fitted gastroscope ( gif - q260 ; olympus , tokyo , japan ) .
after submucosal injection of cerol mixture ( glycerin 10% , fructose 5% ; cheiljedang pharma corp . ,
seoul , korea ) , the first incision was made using a fixed flexible knife ( kachu technology , seoul , korea ) at the center of the stalk .
after exposing the submucosal tissue , the mass was dissected along the stalk using the it-2 knife ( kd-611l ; olympus medical systems co. , tokyo , japan ) ( fig .
macroscopically , the tumor had a three fingers - like shape and was measured 8.76.03.0 cm .
the cut end of the mass revealed multilobulating contoured mass , which was located in the submucosal layer and had yellow color ( fig .
histologically , the neoplasm consisted predominantly of mature looking fat tissues which were in variable sizes and the shape of adipocytic element .
some lipocytes showed big and bizarre nucleuses , suggesting liposarcoma rather than lipoma ( fig .
the tumor had the characteristic features of well - differentiated liposarcoma in general . in some other areas
, there were lobules of mature adipose tissue with a delineated myxoid tumor in the subepithelial stroma .
following esd , the patient was followed up for 4 months by chest ct and egd , and signs of recurrence and metastasis have not been found so far ( fig .
four main subtypes of liposarcoma include well - differentiated liposarcoma , myxoid liposarcoma , pleomorphic liposarcoma , and dedifferentiated liposarcoma .
the only established methods for the diagnosis of liposarcoma are surgical excision and histological examination . although indications for resection have not been established , unconditional resection is not generally recommended because of rare incidence of esophageal liiposarcoma .
the prognosis after the resection of esophageal liposarcoma is not well known because the occurrence of esophageal liposarcoma is so rare that there is no long term follow - up study .
when we reviewed previous records , recurrence occurred in two patients among 15 patients whose medical records were available , so the recurrence rate of esophageal liposarcoma does not seem so high .
although there is no esablished guideline on the follow - up after the resection of esophageal liposarcoma yet , it seems that too frequent monitoring is not required because esophageal liposarcoma is known as a slow - growing tumor . here
, we showed that esd can be a good alternative method for esophageal set to avoid aggressive surgical procedures .
previously esophageal liposarcoma cases were treated by various surgical methods including simple enucleation and partial or total esophagectomy via transcervical , transthoracic , and transgastric routes.1,2 however , such surgical approaches are expensive and more invasive , resulting in longer hospital stays compared to endoscopic methods .
esd is a technique which was originally developed in japan as a method for endoscopic resection of early gastric cancer and adenoma .
the use of esd has been expanded to include the removal of gastric sets following reports of its usefulness in the treatment of gastric sets.3 today , esd is also considered to be a useful therapeutic option for the resection of high grade dysplasia or early cancer in the esophagus .
there have been several studies investigating the efficacy of esd for the resection of esophageal sets .
shi et al.4 reported the usefulness of esd in treating esophageal sets originating from the muscularis propria layer . in this study ,
the curative resection rate was 100% ( 28/28 ) and there were no recurrences during the follow - up of 3 to 27 months .
perforation , which occurred in two cases , were closed with metal endoclips and the patients recovered quickly without surgery .
recently , there have also been some reports about cases for which submucosal tunnel dissection was used to treat upper gastrointestinal sets.5,6 in these studies , sets were successfully resected in patients with tumors sized 2 to 4 cm without severe complications . to our knowledge
, there have been no previous reports about the use of esd for the treatment of esophageal liposarcoma , perhaps due to its rare occurrence .
although the postoperative follow - up has been only 4 months long , there have not been any signs of recurrence or complications .
we believe that the endoscopic approach is superior to more aggressive surgical approaches ( such as esophagectomies ) because it allows more detailed resection as well as early recovery and less pain for the patient .
considering the fact that the use of esd has been increasing recently , we believe this case report is meaningful and will help to validate the use of esd as a feasible option for the treatment of esophageal liposarcomas .
 liposarcoma is one of the most common soft tissue sarcomas occurring in adults , but it rarely occurs in the gastrointestinal tract and more uncommonly in the esophagus . to the best of our knowledge , there are only 19 reported cases of esophageal liposarcoma in the literature published in english language up to the year 2008 , and they were all treated by surgical methods . here 
 , we report a case of primary liposarcoma of the esophagus which was treated with endoscopic submucosal dissection ( esd ) . 
 esd was well tolerated in this patient , suggesting that it may be a therapeutic option for primary esophageal sarcomas . 
INTRODUCTION
CASE REPORT
DISCUSSION
SUPPLEMENTARY DATA