Endoscopic ultrasonographic classification of gastric aberrant pancreas

Gastric aberrant pancreas (GAP) can be demonstrated by its characteristic patterns on endoscopic ultrasonography (EUS). We tried to classify the EUS figures of GAP to provide a useful EUS pattern for diagnosing this disease.

Among 68 cases of GAP suspected by EUS, 13 patients who were proven to have GAP by histology from surgical specimens (4 cases), mucosectomy (6 cases), and biopsy (3 cases) were enrolled. EUS was performed under a standard procedure using an Olympus EU-M3 machine with a 7.5/12 MHz inter-changeable transducer. The essential histological finding of GAP is pancreatic tissue in specimens.

Among 13 patients with GAP (size from 0.7 to 1.6 cm in diameter), 11 tumors were located in the antrum, and 2 were located at the lower body. All 13 tumors arose from the third layer of the gastric wall with an echogenicity higher than the fourth hypoechoic layer. We classified EUS figures of these 13 GAP into 3 types based on the change of the muscular (fourth) layer below the tumor: Type 1 (6 cases), the fourth layer is intact and has a normal thickness; Type 2 (4 cases), the fourth layer has thickened; and Type 3 (3 cases), the fourth layer has thickened, and there are some hyperechoic densities (tubular-like structures) within the fourth layer. Mucosectomy was performed without any complication in 6 cases (four type 1 and two type 2).

EUS figures of our 13 cases of GAP were classified into 3 types which will be helpful in the EUS diagnosis of GAP and can provide information on selecting patients for mucosectomy.