2 Case Reports in Medicine Figure 1: CT scan showing the lesion in the posterior wall of stomach (arrow). Figure 3: (H-E, 40x): Lobular and solid tumor inﬁltrating the muscular layer of gastric wall. Figure 2: Endoscopic image of the submucosal lesion in the posterior wall of the gastric body. cholelithiasis and a lesion (6.8 × 4.8 × 7.3 cm) near the pancreas. There was no evidence of internal calciﬁcations, connection to the pancreatic duct, or ﬂow in the color doppler ultrasonography. However, the CT scan (Figure 1) revealed that the lesion was arising from the posterior wall of the stomach. Upper digestive endoscopy revealed a submucosal, broad-based, and protruding tumor of approximately 7.5 cm, located in the posterior wall of lower gastric body such as a gastrointestinal stromal tumor (GIST) (Figure 2). The patient underwent subtotal gastrectomy and Bill- roth I reconstruction. Macroscopically, the tumor measured 9.0 cm × 7.0 cm × 6.0 cm. The external surface of a well- encapsulated lump of soft solid tumor was smooth and glistening but without gastric mucosal lesion. On serial sectioning, the cut surface was characterized by several amorphous fragments of ﬁbrous tissue. Histologically, the tumor was composed of round and spindle-shaped myoﬁ- broblastic cells, diﬀusely scattered inﬂammatory cells, and many vascular structures (Figures 3 and 4). The tumor Figure 4: (H-E, 200x): Solid tumor cytologically composed of a compact proliferation of spindle cells arranged in a fascicular growth pattern. cells showed positive immunoreactivity for vimentin and anaplastic lymphoma kinase (ALK), while being negative for c-kit, CD34, desmin, smooth muscle actin (SMA), and S- 100 (Figure 5). Ki-67 labeling index was approximately 30%. Lymph nodes (11) found along the gastric vessels in the omentum were all negative for tumor. The ﬁnal diagnosis was consistent with IMT that origi- nated from the gastric wall. The patient had an uneventful postoperative period and has been followed up without any recurrence. 3. Discussion The primary inﬂammatory myoﬁbroblastic tumor (IMT) is a very rare neoplasm in adults and the exact nature of the disease is not yet completely understood [12]. It was once accepted that IMT is primarily a disease of children and young adults and commonly occurs in the lungs [13, 14].