Suspicion of microscopic colitis raised by sonographic examination

This report describes the case of a 57-year-old woman who was incidentally identified as having lymphocytic colitis after she underwent routine transabdominal sonographic examination. She initially reported having no irregularities in her bowel movements. Sonography revealed the following nonspecific findings: watery stool in the entire colon, slight thickening of the hypoechoic mucosal layer and moderate thickening of the hyperechoic submucosal layer of the colon, and no pathologic findings in the small intestine. On additional questioning, the patient said that she had had watery diarrhea for the last 10 years, with as many as 10 bowel movements daily. Endoscopic examination and biopsy were performed. Histopathologic examination of biopsy specimens showed lymphocytic infiltration of the mucosa and some collagen deposits, consistent with a diagnosis of lymphocytic colitis. Treatment was begun with loperamide, sulfasalazine, and budesonide. Within 3 weeks of the start of treatment, the number of bowel movements decreased to 1-2 daily. Follow-up sonography at that time revealed normalization of the bowel contents and disappearance of the thickened submucosal layer of the colon. Nonspecific sonographic findings like those in this case lead to the need to rule out various diseases through further appropriate evaluations to identify the correct diagnosis.