Lymphocytic Colitis : Microscopic
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Lymphocytic colitis (LC) has overlapping histologic features with collagenous colitis (CC). However, in contrast to CC, the damage to surface epithelium and intraepithelial lymphocytosis are more pronounced in LC. The subepithelial collagen layer is not thickened. The lamina propria shows increased number of plasma cells. Eosinophils in the lamina propria may be fewer in number than in CC or altogether absent. The crypt architecture is intact.
Intraepithelial lymphocytosis and surface epithelial damage may be patchy in distribution. One must avoid areas immediately overlying lymphoid follicles for evaluating intraepithelial lymphocytes. Such foci normally have many intraepithelial lymphocytes. Some cases of LC may show focal cryptitis or a rare crypt abscess. More than focal neutrophilic inflammation should raise the possibility of another diagnosis.
The differential diagnosis of lymphocytic colitis includes: resolving infectious colitis, chronic food- or water-borne diarrhea (aka colonic epithelial lymphocytosis), Crohn disease, collagenous colitis, and normal colonic mucosa overlying a lymphoid follicle.
Image credit: Copyright ©2013 Michael Bonert, MD - Own work, CC BY-SA 3.0
Intraepithelial lymphocytosis and surface epithelial damage may be patchy in distribution. One must avoid areas immediately overlying lymphoid follicles for evaluating intraepithelial lymphocytes. Such foci normally have many intraepithelial lymphocytes. Some cases of LC may show focal cryptitis or a rare crypt abscess. More than focal neutrophilic inflammation should raise the possibility of another diagnosis.
The differential diagnosis of lymphocytic colitis includes: resolving infectious colitis, chronic food- or water-borne diarrhea (aka colonic epithelial lymphocytosis), Crohn disease, collagenous colitis, and normal colonic mucosa overlying a lymphoid follicle.
Image credit: Copyright ©2013 Michael Bonert, MD - Own work, CC BY-SA 3.0