New insights and challenges in microscopic colitis.

Area of Science:

• Gastroenterology
• Pathology

Background:

• Microscopic colitis (MC) presents as chronic, non-bloody diarrhea, yet endoscopic examination appears normal.
• Histopathology reveals two subtypes: collagenous colitis (CC) and lymphocytic colitis (LC), often clinically indistinguishable.
• MC typically affects middle-aged individuals, with a potential female predominance, though etiology remains unclear and may involve non-autoimmune factors.

Purpose of the Study:

• To review the histopathological and clinical features of microscopic colitis.
• To discuss the diagnosis and management strategies for MC.
• To address recent discussions on the overdiagnosis and societal costs associated with MC.

Main Methods:

• Literature review of histopathological findings in MC.
• Analysis of clinical presentations and diagnostic criteria for MC.
• Discussion of current management approaches and emerging perspectives on MC etiology.

Main Results:

• MC subtypes (CC and LC) are defined by distinct microscopic mucosal changes.
• Clinical presentation can vary, including asymptomatic cases or symptoms other than diarrhea.
• The role of autoimmunity versus general mucosal irritant response in MC is debated.

Conclusions:

• Accurate diagnosis of MC relies on histopathological examination.
• Understanding diverse etiologies is crucial for appropriate patient management.
• Further research is needed to refine MC classification and treatment, considering potential overdiagnosis concerns.