{'fraction_non_alphanumeric': 0.033105888299216575, 'fraction_numerical': 0.015036643922163254, 'mean_word_length': 4.919970082273747, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Gastrointestinal Stromal Tumor of the Stomach with an Abscess Excised by Laparoscopic Surgery

Gastrointestinal stromal tumors (GISTs) of the stomach presenting as an intra-abdominal abscess are extremely rare. We herein report a case that underwent successful laparoscopic resection of gastric GIST presenting with an intra-abdominal abscess. A 70-year-old man presented with a 3-day history of acute upper abdominal pain with a fever. Laboratory data showed an elevated white blood cell count and C-reactive protein level. A CT scan revealed a mass of mixed solid and fluid components, measuring 5.5 cm, in the adjacent lesser curvature of the stomach. He was diagnosed as having an intra-abdominal abscess, and antibiotic therapy was administered. Consequently, his symptoms were relieved and a CT scan on the 7th day showed that the mass reduced and became homogenous. According to the results of a fine-needle aspiration biopsy, the tumor was suspected to be a GIST. Laparoscopic surgery with the 5-port approach was performed. The tumor existed in the lesser curvature of the stomach, and was excised en bloc with the omentum and gastric wall by wedge resection. The tumor measured 3.0 cm in diameter and originated from the serosal layer of the stomach. Histological findings showed spindle cells with a stromal growth pattern that was positive for c-kit (CD 117) and CD 34. The postoperative course was uneventful, and no recurrence has been noted in the 2 years since the operation. This is the first report of a case with gastric GIST with an intra-abdominal abscess that was successfully treated by laparoscopic surgery.


Introduction
Gastrointestinal stromal tumors (GISTs) are the most common sarcoma of the gastrointestinal tract. GISTs are malignancies that arise from intestinal cells of Cajal, which are pace maker cells in the bowel wall, and the stomach is the most common location of GISTs [1,2]. Surgical resection is the primary and only curative treatment of GISTs without dissemination or distant metastases. For relatively small gastric GISTs, laparoscopic resection has been reported to be a safe and effective treatment option associated with a significantly shorter hospital stay [3,4]. However, in cases with bulky or complicated GISTs, the indications for laparoscopic surgery remain controversial since laparoscopic procedures may be difficult in such cases, or even compromise the oncologic outcomes [5][6][7].
GISTs involving the stomach presenting as an intra-abdominal abscess are extremely rare, and only 7 cases have been reported in the English literature [8][9][10][11][12][13][14]. To the best of our knowledge, all of these reported cases were treated by conventional open surgery. We herein report the first case treated by laparoscopic surgery for gastric GIST presenting with an intra-abdominal abscess.

Case Presentation
A 70-year-old man presented with a 3-day history of acute upper abdominal pain. He had a fever of 38.1°C and tenderness in the upper abdomen. The patient had not been taking medications and his past history was unremarkable. Laboratory data showed a white blood cell count of 14,000/mm 3 and C-reactive protein level of 11.8 mg/dl. A contrast-enhanced CT scan of the abdomen revealed a mass of mixed solid and fluid components, measuring 5.5 cm, adjacent to the lesser curvature of the stomach ( fig. 1a). He underwent gastrointestinal endoscopy, which revealed a submucosal tumor near the gastric angle without an ulcer or fistula. According to these findings, he was diagnosed as having an intra-abdominal abscess, and sulbactam/cefoperazone sodium 2 g/day was administered for 10 days. Consequently, the fever decreased, his symptoms relieved and the laboratory data improved. A contrastenhanced CT scan on the 7th day showed mass reduction (5.5-3.5 cm) ( fig. 1b). An endoscopic ultrasound examination was performed on the 30th day, which showed a submucosal tumor with mixed hypoechoic changes ( fig. 1c). A fine-needle aspiration biopsy was performed, and the tumor was diagnosed as GIST.
Laparoscopic surgery with the 5-port approach ( fig. 2a) was performed to excise the tumor on the 70th day from the first presentation. Laparoscopic findings showed that the tumor existed in the lesser curvature of the stomach and adhered to the omentum. Wedge resection of the stomach was performed using a linear stapler, and the tumor was excised en bloc with the omentum and gastric wall ( fig. 2b-d).
The excised tumor measured 3.0 × 2.5 cm in diameter and originated from the serosal layer of the stomach, without an obvious fistula between the gastric lumen and the tumor. Histological findings showed spindle cells with a stromal growth pattern without necrosis ( fig. 3a). The tumor was positive for c-kit (CD 117) and CD 34 ( fig. 3b, c), with a Ki-67 index of 8% and mitosis of <5/50 HPF, and was accordingly diagnosed as low-risk GIST. The postoperative course was uneventful, and the patient was discharged on postoperative day 12. Imatinib mesylate was administered as adjuvant treatment, and no recurrence has been noted for 2 years after operation.

Discussion
GISTs are understood to be specific KIT-or PDFGRA-driven mesenchymal gastrointestinal tract tumors, and a majority of these tumors (more than 60%) occur in the stomach [1,2]. The availability of a KIT and PDGFRA tyrosine kinase inhibitor, imatinib mesylate, has dramatically changed treatment strategies for metastatic or unresectable GISTs [15]; however, surgical resection remains the only curative treatment.
Cases of GISTs involving the stomach presenting as an intra-abdominal abscess are extremely rare, and only 7 cases have been reported in the English literature (table 1) [8][9][10][11][12][13][14]. In some cases with GISTs, tumor degeneration or necrosis can result in bleeding into the gastrointestinal lumen or peritoneum space, and bleeding into the intra-abdominal space can cause an intra-abdominal abscess. Five of 7 reported cases had a tumor with an ulcer or fistula in the lumen on macroscopic findings, and tumor necrosis was observed in 5 cases on histological examination. The presence of an ulcer, fistula, and necrosis may increase the risk of abscess formation; however, the present case and the case reported by Swain et al. [9] had no ulcer, fistula, or necrosis. The precise reason for abscess formation in these cases was unclear. We speculate that a minor hemorrhage occurred around the tumor, and subsequently bacterial infection via the gastrointestinal tract or blood stream might have resulted in abscess formation in these two cases.
For relatively small gastric GISTs, laparoscopic resection has been reported to be associated with favorable short-term outcomes without compromising the oncologic results [3,4]. However, the indications for laparoscopic surgery should be carefully discussed for cases with bulky (larger than 5 cm) and high-risk tumors [5]. Therefore, most surgeons prefer conventional open surgery for large or complicated tumors to avoid tumor manipulation, which may cause dissemination or port site metastases [6,7].
In the present case, the tumor and abscess coexisted at the time of initial hospitalization; however, the abscess was controlled by intravenous antibiotic therapy, and consequently the tumor was safely excised by laparoscopic surgery with sufficient surgical margins. To the best of our knowledge, this is the first report written in the English language of a case with gastric GIST with an intra-abdominal abscess treated by laparoscopic surgery.

Conclusion
We herein reported the case of stomach GIST with an intra-abdominal abscess that was successfully excised by laparoscopic surgery.

Statement of Ethics
The authors have no ethical conflicts to disclosure. Informed consent was obtained from the presented patient.

Disclosure Statement
The authors have no conflicts of interest to declare.