What is the differential diagnosis?
Although less likely given the focal nature of the abnormality and the central apparent ulceration, gastric lymphoma should be considered. A GIST tumour can centrally ulcerate / cavitate. Gastric metastases are uncommon.
CT of the abdomen demonstrates a mass arising from the greater curvature of the body of the stomach. It is centrally ulcerated with locules of gas and contrast seen within it, but without evidence of perforation. It is a focal abnormality with thick heaped-up shoulders.
At the splenic hilum there appears to be an enlarged lymph node (this should be confirmed on thin slice and coronal reformats). No convincing evidence of metastatic disease.
The left kidney is atrophic and contains a number of what appear to be hyperdense cysts (which should be confirmed on ultrasound). The right kidney has a large simple cyst.