As the name suggests, microscopic colitis requires histologic evaluation for diagnosis. The two most well-established histologic patterns are collagenous colitis and lymphocytic colitis.

Diagnosis occurs in 10%-14% of patients with chronic diarrhea and macroscopically normal colonoscopy; ... 1.07). These findings were related more to collagenous colitis than its lymphocytic ...

The latter feature is consistent with a diagnosis of collagenous colitis, one of the two types of MC. The other type of MC is lymphocytic colitis, which lacks the prominent collagen band.