Gastrointestinal stromal tumor mimicking arteriovenous malformation of the jejunum

Abstract

There have been case reports of small intestinal gastrointestinal stromal tumors (GISTs) complicated with arteriovenous malformation (AVM) and angiodysplasia and exhibiting intense tumor staining. Herein we report a GIST of the small intestine that showed tumor staining and early venous return on imaging studies, and so the patient was suspected to have AVM. A 62-year-old male presented with intermittent pain in the left abdominal region. Contrast-enhanced computed tomography revealed a 15-mm-long spindle-shaped mass showing intense tumor staining and early venous return through the jejunal vein. In the arterial phase, the attenuation value of the tumor was 250 Hounsfield units. Color Doppler ultrasonography simultaneously delineated vessels extending from the serosal side and turbulent signals showing a mosaic pattern in the tumor. On angiography, intense staining was observed in the peripheral part of the second branch of the jejunal artery. Although these findings suggested AVM, the tumor was diagnosed as a GIST based on pathological examination of the resected specimens. In this case, no AVM or change in vascular density was noted despite the careful examination of pathological specimens, and the cause of the tumor staining remained unknown.

Keywords: Arteriovenous malformation; Contrast-enhanced computed tomography; Contrast-enhanced ultrasonography; Gastrointestinal stromal tumor.

Fig. 1

a CECT revealed a long spindle-shaped mass showing intense tumor staining and early venous return through the jejunal vein, which was continuous with the mass (arrow) in the early phase. b Horizontal US scan revealed a low-echoic mass (arrow) with a clear margin in the jejunal wall. Horizontal color Doppler US scan simultaneously delineated vessels extending from the serosal side and turbulent signals showing a mosaic pattern in the mass. c Angiographic CT delineated a large jejunal vein (arrowhead) continuous with the mass nearly simultaneously with injection of the contrast medium.

Fig. 2

a On gross examination of the resected sample, the mass measured 14 × 9 mm in the mucosal side. b Histopathologically, the tumor cells had a relatively short elliptical shape, a large, hyperchromatic and somewhat irregularly shaped nucleus, and spindle-shaped cytoplasm (HE stain, ×100).

Fig. 3

Time-attenuation curves of small intestinal GISTs <25 mm in size previously experienced in 3 cases (arrows). In the arterial phase 35 s after the contrast medium, the enhancement value of the tumor in our case showed higher than the enhancement values of the tumors in cases 1–3.