Advanced gastric adenocarcinoma mimicking a submucosal tumor.

mitted for evaluation of a gastric lesion incidentally noted on upper gastrointesti− nal endoscopic examination during a rou− tine health evaluation. At initial endosco− py, a 13−mm submucosal tumor covered with benign−appearing mucosa was found (l" Figure 1). Endoscopic ultraso− nography (EUS) demonstrated a 13.0− mm homogenous, circumscribed hypo− echogenic lesion rising from the fourth sonographic layer, and this lesion was thought from its morphology to be mus− cularis propria (l" Figure 2). Initial biopsy specimens were negative for any neoplas− tic degeneration. Follow−up endoscopy with mucosal biopsy was performed 13 months after the initial examination. This revealed that the margin of the tu− mor had become irregular, and the cen− tral erythema was more prominent (l" Figure 3). The specimens taken from the central depression revealed poorly differentiated adenocarcinoma. At lapa− rotomy, serous surface invasion was strongly suspected on the gastric wall al− though no ascites or liver metastasis were present. Distal gastrectomy with regional lymph node dissection, cholecystectomy, and gastroduodenostomy were per− formed. The histopathologic specimen was consistent with moderately differen− tiated adenocarcinoma, partially mixed with poorly differentiated adenocarci− noma, without focal lymph or vascular invasion. The tumor extended to the sub− serosa but did not involve the serosa (l" Figures 4 a, b). All dissected lymph nodes were free of tumor. Although gastric cancer mimicking a sub− mucosal tumor (GCSMT) is extremely rare [1] and it is difficult to obtain an ade− quate sample from the underlying lesion [2], the present case indicates that the finding of a small SMT with central ery− thema or granular changes and hypoe− chogenicity as defined by endoscopy and EUS should raise a suspicion of GCSMT. Consistently, previous reports have shown that GCSMTs were 33 mm or less in diameter at diagnosis, and all had cen− tral irregular erythematous or granular mucosa changes [3]. If the diagnosis is uncertain, the use of aggressive tech− niques instead of EUS alone, including EUS−guided biopsy, diagnostic endo− scopic mucosal resection, possibly with surgical resection, should be advocated [4], and close follow−up is recommended.