This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: GIT and hepatobiliary system, Subject name: Radiology
A 72-year-old man presents to his GP with increasing dyspepsia and weight loss. He has not experienced any other GI symptoms and physical examination is unremarkable. A barium meal is performed with the administration of intravenous Buscopan. The oesophagus is normal in appearance but a 'bull&;s eye' lesion is noted in the gastric mucosa. Which one of the following is not a recognised cause of this appearance? 
Select and explain. 
A. Gastric carcinoma, B. Gastrointestinal stromal tumour (GIST), C. Magenstrasse, D. Melanoma metastases
C: Magenstrasse
Answer: C: Magenstrasse 
Explanation: Magenstrasse refers to the normal longitudinal mucosal folds seen adjacent to the lesser curve of the stomach during a barium meal. The 'bull&;s eye' appearance seen during a barium meal is due to a central ulcer in an elevated area of submucosa. A GIST may well have this appearance and neurofibromatosis can cause single or multiple target lesions. Melanoma is the commonest cause of submucosal gastric metastases.