© Georg Thieme Verlag KG Stuttgart · New York
Gastric inflammatory myofibroblastic tumor masquerading as a pancreatic cystic neoplasm
07 October 2010 (online)
A 56-year-old man presented with epigastric pain since 2 weeks. Esophagogastroduodenoscopy (EGD) revealed a 3-cm submucosal mass in the posterior wall of the gastric body. Abdominal ultrasound showed a multilocular cystic lesion (10 × 6 × 9 cm) in the pancreatic tail. Endoscopic ultrasound (EUS) confirmed a multicystic lesion arising from the pancreas ([Fig. 1]).
Fig. 1 Endoscopic ultrasound showing a multicystic lesion intermixed with a solid tumor.
The cysts were macrocystic in nature, ranging from 1 cm to 2 cm in size, and were intermixed with solid tumor. There was no evidence of internal calcifications or connection to the pancreatic duct. The EUS features were suggestive of a mucinous cystadenocarcinoma of the pancreas. However, a subsequent computed tomography scan revealed that the multilocular lesion was arising from the posterior wall of the stomach; this was confirmed on laparotomy ([Fig. 2]).
Fig. 2 Computed tomography (CT) appearances of the gastric inflammatory myofibroblastic tumor.
Macroscopically, the tumor was a lobulated, circumscribed mass with a mix of solid and cystic components ([Fig. 3]).
Fig. 3 Macroscopic appearance of the lobulated, circumscribed mass with mixed solid and cystic components.
Histologically, it consisted of proliferating spindle cells in a fibromyxoid stroma, admixed with a moderate amount of mixed inflammatory cellular infiltrate, compatible with a gastric inflammatory myofibroblastic tumor (IMT).
IMTs are rare neoplasms in adults. Microscopically, they are composed of spindle cells with abundant cytoplasm on an inflammatory background . The diagnosis of IMT is often difficult and there are scarce reports of the EUS appearances. A well-defined hypoechoic mass arising from the submucosa, similar to gastrointestinal stromal tumors, has been described  . However, a multilocular cystic appearance along with solid components has not been previously documented in the literature. In the present case, the lesion was initially mistaken to be a pancreatic cystic neoplasm and a retrospective review of the EUS images demonstrated that the tumor was indeed arising from the gastric wall. The mainstay of treatment for IMT is resection with clear margins  . After complete resection, the prognosis of IMT is generally good with a low risk of distant metastasis   .
Competing interests: None
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E. K. W. Ng
Department of Surgery
Prince of Wales Hospital
Shatin New Territories
Hong Kong SAR