Cat scratch colon – A very rare complication of colonoscopy

Background: In recent years a new kind of lesion of the colon diagnosed during colonoscopy has been described. The findings are characterised by superficial bright red linear marks in the mucosa of the colon. These marks are mostly located in the ascending colon and cecum and are named „cat scratch colon“ because of their macroscopic aspect resembling scratches caused by cat's claws. Only very few cases have been reported so far in the literature.

Case report: We report on a case of a 67 year old woman presenting with lower abdominal pain and diarrhoea for 5 weeks who was referred to colonoscopy. The patient had lost twelve kg of weight during the last five weeks. Physical examination revealed no abnormalities. Blood samples showed elevated liver parameters (GOT, GPT and γGT) and ultrasound an enlargement of the liver. At colonoscopy, multiple diverticula in the sigmoid and descending colon were found. During intubation of the cecum and ascending colon, multiple, bright red corkscrew like lesions with extravasation of fresh blood were observed. The biopsies taken showed normal mucosa with no sign of colitis or other abnormalities. Based on the typical macroscopic appearance of the lesion we referred to the lesions as „cat scratch colon„.

Discussion: It is suspected that these superficial and harmless lesions, occurring with a prevalence of an estimated 0,25%, result from barotrauma by the insufflation of air during colonoscopy. The occurrence of „cat scratch colon„ is usually associated with a normal histopathology of biopsies from the mucosal lesion. The few cases reported occurred in a less compliant right colon, caused for example by collagenous colitis, compression due to liver enlargement in metastatic liver and diversion colitis. The patient did not develop any relevant symptoms after colonoscopy.

Literature:

M. McDonnell et. al., Cat scratch colon. Endoscopy 2007; 39: 459–461