[A 67-year-old patient with diarrhoea and constipation without any pathological findings in virtual colonoscopy].

Virtual colonoscopy provides a computer-simulated endoluminal perspective of the air-filled, distended colon using modern CT scanning (spiral CT). According to recent studies the sensitivity and specificity of this technique are high for adenomatous polyps > or = 10 mm. A 67-year-old patient was admitted to our hospital because of diarrhoea and constipation, associated with abdominal pain in the lower right abdomen. Prior to admission the patient had undergone virtual colonoscopy in a specialised radiological practice which had detected no abnormalities apart from colonic diverticulosis. However, conventional video-colonoscopy revealed a subtotal circular malignant stenosis in the region of the right colonic flexure. A poorly differentiated adenocarcinoma was diagnosed histologically. Staging showed peritoneal carcinosis with infiltration of the right ureter and lymphangiosis carcinomatosa of the pectoral lobe of the left lung. After right hemicolectomy because of metastasised carcinoma of the ascending colon (pT4pN1pM1) we started palliative chemotherapy with oxaliplatin, 5-fluorouracil and leucovorin. The risk of misdiagnosis by virtual colonoscopy is clearly increased in patients with subtotal tumour stenosis of the ascending colon. Conventional video-colonoscopy remains the gold standard for the diagnosis of colorectal carcinoma.