Introduction Caecal perforation may represent a complication of stenotic colon carcinoma in any of its segments. It is associated with the conspicuous diffusion in seg- ments proximal to the obstruction (1). Usually, it determines an insidious onset of the neoplastic disease that, prior to this manifestation, was referred to as constipation. The high rate of mortality associated with this event is linked to the transition of faecal material in the peritoneal cavity that consequently evolves in pe- ritonitis (2). We present the case of a patient suffering from a sub-occlusive carcinoma of the left colon and hypoto- nic colitis, due to a long period of laxative abuse, stu- died with Computerized Tomography (CT), and de- veloping caecal perforation. Case report A 51-year-old woman was admitted to the Emergency Room of our University Hospital, with moderate abdominal pain lasting approximately a few hours and obstruction to faeces and air. The general conditions of the patient were good. The physical exa- mination showed a soft abdomen, with moderate pain exacerbation but no evident signs of peritonism. The lab tests were within normal limits; specifi- cally the number of white blood cells (6000/mm 3 ) and the leucocyte formula were found normal. The history of the patient reported years of con- stipation relieved by the use of phenolphtalein laxati- ves taken without medical control. According to what the patient declared, the constipation had slowly wor- sened in the previous weeks leading to the present cli- nical conditions. Basal CT exam demonstrated a large amount of faecal material diffused in the peritoneal cavity. At the level of the proximal descending colon CT showed an irregular thickening of bowel walls and lymphagitic infiltration stripes within of the perivisceral fat. Hy- perdensity of the peritoneal fat with a low fluid quan- tity. The patient underwent surgical treatment which showed the peritoneal cavity was full of excessive fae- cal material, due to the perforation of the caecum, whose linings were in a necrosis stage, diffusing to the ascending colon; the peritoneum showed haematosis and congestion, and was wet with mildly thick fluid. Stercorary aseptic peritonitis due to diastatic caecal perforation: computed tomography findings Giuseppe Runza 1 , Nicola Nicastro 1 , Alfredo D’Andrea 1 , Filippo Barbiera 1 , Laura Damiani 1 , Laura La Fata 1 , Alessandro Palumbo 2 , Filippo Cademartiri 2 , Massimo Midiri 1 1 Department of Radiology, University Hospital, Palermo, Italy; 2 Department of Radiology, University Hospital, Parma, Italy Abstract. Caecal perforation is a complication secondary to colon obstruction. It may present with insidious clinical features and may be associated with chronic constipation. The event may become severe due to the peritonitic development. We present a case of caecal perforation associated with sub-occlusive carcinoma of the left colon and hypotonic colitis caused by chronic lavative abuse, demonstrated with Computed Tomog- raphy. (www.actabiomedica.it) Key words: Computed Tomography, caecal perforation, laxativa abuse, colon carcinoma C A S E R E P O R T ACTA BIOMED 2006; 77; 106-108 © Mattioli 1885