A pilot study of confocal laser endomicroscopy for diagnosing gastrointestinal mucosa-associated lymphoid tissue (MALT) lymphoma.

Abstract

Patients with gastrointestinal mucosa-associated lymphoid tissue (MALT) lymphoma require lifelong endoscopic follow-up. This study aimed to establish and evaluate confocal laser endomicroscopy (CLE) criteria for gastrointestinal MALT lymphoma. This prospective trial was conducted after IRB approval at the Medical University of Vienna. Twenty-four consecutive patients (14 males and 10 females, median age 65years) referred for staging or follow-up of (former) gastrointestinal MALT lymphoma underwent endosonography (EUS) and CLE including white light endoscopy (WLE) and conventional biopsy sampling of the upper gastrointestinal tract. CLE criteria of the disease were based on the first five patients with histologically proven MALT lymphoma. All CLE datasets were reviewed separately by two CLE experts. The diagnostic modalities were compared using conventional histology as the gold standard. Sixty-two percentages had a positive diagnosis of MALT lymphoma based on histology. The sensitivity was 80% for EUS (0.51-0.95), 100% for WLE (0.75-1) and 93% for CLE (0.66-1); the specificity was 67% for EUS (0.31-0.91), 23% for WLE (0.04-0.60) and 100% for CLE (0.63-1). The agreement with histology was moderate for EUS (kappa 0.47, p=0.02), fair for WLE (kappa 0.26, p=0.06) and almost perfect for CLE (kappa 0.91, p<0.01). Expert evaluation identified all but one case of MALT lymphoma with excellent interobserver agreement (kappa 0.89, p<0.01). In the case missed by CLE, MALT lymphoma involvement was restricted to deep tissue structures. Despite minor technical limitations, CLE is a promising alternative to conventional biopsy sampling in patients with gastrointestinal MALT lymphoma. CLINICALTRIALS. NCT01583699.