Current Evidence, Diagnostic Challenges, and Contemporary Management of Lymphocytic Colitis: A Case Report and Literature Review.

Lymphocytic colitis (LC) is a subtype of microscopic colitis characterized by chronic, typically non-bloody, watery diarrhea and increased intraepithelial lymphocytes despite a macroscopically normal or near-normal colon. This clinicopathological discordance creates a major diagnostic challenge because clinically important symptoms may occur without visible mucosal abnormalities, leading to missed diagnoses when colonic biopsies are not obtained. Although recognition of LC has increased, important uncertainties remain regarding its epidemiology, pathogenesis, medication associations, natural history, and optimal management, particularly in recurrent or treatment-dependent disease. This case report of a 39-year-old man and narrative review synthesizes contemporary evidence on LC, emphasizing epidemiology, pathogenesis, clinical presentation, diagnostic approach, histopathological criteria, treatment, and evidence gaps. Recent evidence supports budesonide as the preferred first-line therapy for symptomatic disease, while emerging real-world data suggest potential roles for advanced therapies in selected budesonide-refractory or budesonide-dependent patients. However, these data largely come from mixed microscopic colitis populations. Epidemiological evidence remains concentrated in North America and Europe, and data from Africa, including Nigeria, are sparse. Improved clinical recognition, standardized biopsy practices, consistent histopathological assessment, LC-specific therapeutic research, and geographically diverse epidemiological studies are needed to reduce diagnostic delay and improve long-term management.