Focal active colitis: Diagnostic relevance and long-term clinical outcomes

Focal active colitis (FAC) is a histopathologic finding characterized by focal neutrophilic crypt injury without chronic architectural changes. Its clinical implications, particularly its association with inflammatory bowel disease (IBD), remain debated.

We retrospectively reviewed colorectal biopsies diagnosed as FAC (2005-2024) at a tertiary center in Lebanon. Adult patients (>18 years) with isolated FAC and available clinical follow-up were included. Clinical outcomes, endoscopy, and subsequent diagnoses were analyzed.

419 patients had complete follow-up data. Mean age was 52.5 years; 51.5% were female. Abdominal pain was the most common presentation (57.5%). Colonoscopy was normal in 73%. During a mean 26-month follow-up, 9 patients (2.15%) developed IBD (4 Crohn's disease, 3 ulcerative colitis, 2 unclassified). IBS was diagnosed in 33.2%, infectious colitis in 11.2%, drug-induced colitis in 8.6%, diverticular disease in 4.5%, and ischemic colitis in 0.7%. 25.3% had no identifiable etiology with negative follow-up. FAC was incidental in 10.5% and persistent in 3.8%. No histologic features predicted progression to IBD.

In this 19-year, 419-patient study, FAC was most often linked to IBS, infection, or drug-induced injury, with only 2.15% progressing to IBD. No predictive histologic features were identified. FAC remains a nonspecific finding; careful follow-up is warranted in symptomatic patients, while incidental cases are usually clinically insignificant.