Endosonographic Features of Advanced Gastric Carcinoma Invading the Colon: Is it Easy to Differentiate from Pancreatic Invasion?

Endoscopic ultrasonographic (EUS) image of a T4 gastric carcinoma on the posterior wall of the angulus taken using a GF-UM200 (7.5 MHz) echoendoscope (Olympus, Tokyo, Japan). The linear hypoechoic area along the outer tumor margin (arrow) was first interpreted as the main pancreatic duct of an invaded pancreatic body, but surprisingly, the actual pancreas was demonstrated soon afterwards in its normal position.

Histopathological examination proved that the linear hypoechoic area was consistent with the muscularis propria of the colon (arrow) (hematoxylin and eosin, original magnification × 5). Another patient recently presenting with the same EUS features was diagnosed correctly.