SPONTANEOUS PASSAGE OF A COLON CAST IN THE ABSENCE OF ABDOMINAL ANEURYSM

The spontaneous passage of colon cast from a 76-year-old Japanese fema le patient is reported. Macroscopically, the colon cast was shaped lik e the airbladder of a fish. Histopathologically, the cast consisted of degenerated colonal mucosa, including glands. No inflammatory reactio n was apparent. The patient lacked any evidence of abdominal aneurysm. Since there have been only five reported cases of colon cast in the l iterature, and since in all of those association with abdominal aneury sms was always described, the present study represents the first repor t demonstrating the formation of a colon cast in the absence of associ ated abdominal aneurysm. However, the patient was found to exhibit sev eral risk factors for ischemic colitis, such as arteriosclerosis on th e wall of the abdominal aorta, chronic constipation, and colonic steno sis. Her colonal mucosal surface, indeed, suggested ischemic colitis. This case report, therefore, indicates that ischemic colitis, due to v arious causes, may be responsible for the formation of colon casts, an d that the presence of an abdominal aneurysm is not necessarily a prer equisite for colon cast formation. This report may contribute to a bet ter understanding of the pathogenesis of colon casts.