Colonic epithelial lymphocytosis without a thickened subepithelial collagen table - A clinicopathologic study of 40 cases supporting a heterogeneous entity

Lymphocytic colitis (LC) is classically described as a triad of chronic non bloody, watery diarrhea, normal or nearly normal endoscopy findings, and co lonic epithelial lymphocytosis without a thickened subepithelial collagen t able (SECT). It is unknown how often patients with colonic epithelial lymph ocytosis without a thickened SECT actually present with this classic triad. Cases diagnosed histologically as lymphocytic or microscopic colitis were reviewed. Criteria for inclusion were the presence of at least 15 surface l ymphocytes per 100 epithelial cells and the absence of a thickened SECT (<1 2 mu m). Clinical features and course were recorded by chart review and tel ephone follow-up. Forty patients met the inclusion criteria, including 25 w omen and 15 men with a mean age of 63.2 years (range, 25-83 years). Twenty- eight patients had the classic triad and were designated as having classic LC. The other 12 patients fulfilled the histologic criteria but not the cli nical or endoscopic criteria for classic LC and were classified as having a typical LC (constipation, five patients; macroscopic colitis at endoscopy, five patients; hematochezia, one patient; and incidental finding, one patie nt). Clinically, patients with classic LC were predominantly women and had a higher incidence of autoimmune disease (p = 0.03) than did those with aty pical LC. Histologically, surface eosinophilia was significantly greater in patients with classic LC (p = 0.04). Twenty patients were using nonsteroid al antiinflammatory drugs at the time of their colonic biopsy. Surface epit helial lymphocyte counts were higher in these patients, particularly in the distal sigmoid colon (p = 0.02). Fourteen patients had associated autoimmu ne disease, including three patients with sprue diagnosed by small bowel bi opsy, all of whom responded to gluten withdrawal. Diarrhea present in 25 pa tients, without documented evidence of celiac sprue, was self-limited in fi ve, resolved with treatment in three, required intermittent treatment in ei ght, daily treatment in five, and was refractory to treatment in four. All eight patients who experienced spontaneous or treatment-related symptom res olution had classic LC. No histologic feature correlated with clinical cour se. In conclusion, our study shows that colonic epithelial lymphocytosis wi thout a thickened SECT is a histologic finding seen in a heterogeneous grou p of patients. Within this heterogeneous group is a distinct subset of pati ents who have the classic clinicopathologic triad of LC. This subset of pat ients has striking similarities to patients with collagenous colitis, lendi ng further support to a close relationship between these two entities. Atyp ical LC comprises a heterogeneous group and includes patients with idiopath ic constipation, coexisting LC and inflammatory bowel disease, and possibly infectious colitides. Because of the clinical heterogeneity among our stud y population, the descriptive term colonic epithelial lymphocytosis may be a more prudent diagnosis than lymphocytic colitis in the absence of adequat e clinical information.