Colitis Nucleomigrans: A Proposal for The Third Type of Microscopic Colitis
Author(s): Mitsuhiro Tachibana, Yutaka Tsutsumi
Recently, we proposed the third entity of microscopic colitis (MC), termed colitis nucleomigrans (CN). The present review describes clinicopathological features of CN. CN shares clinical and endoscopic features of MC with collagenous colitis and lymphocytic colitis. We analyzed endoscopic biopsy specimens of nonspecific colitis clinically manifesting chronic watery diarrhea or inflammatory bowel disease (IBD)-like symptoms, but with minor endoscopic abnormality. The histopathological criteria of CN are as follows: a) chained nuclear migration to the middle part of the surface-lining columnar epithelia, b) apoptotic nuclear debris scattered below the nuclei, and c) mild to moderate chronic inflammation in the lamina propria. Thirty-three patients (M: F=20:13, median 63 years; range 17-88) fulfilled the above criteria. Seven cases accompanied MC-like clinical/endoscopic features. Mucosal reddening with or without erosions/aphthae was endoscopically observed in the remaining 26 cases with IBD-like clinical features: occult/gross hematochezia (n=19), abdominal pain (n=2) and mucin secretion (n=2). Apoptotic debris immunoreactive for cleaved caspase-3 appeared more frequently in IBD-like CN than in MC-like CN. CD8-positive intraepithelial lymphocytes were comparable in both types. Proton pump inhibitors (PPIs) were administered in five (71%) CN cases with MC-like features, and the diarrhea improved after cessation of PPIs in three. In IBD-like CN cases, eight (31%) received PPIs. Altered apoptotic processes in the colorectal surface-lining epithelia, predominantly with a debris pattern of apoptosis, may be involved in the pathogenesis. Mechanisms of nuclear migration to the unusual position and the impairment of nuclear anchoring to the basal situation in the surface-lining epithelia remain to be established.