Gastrointestinal Involvement in Mantle Cell Lymphoma (MCL). A Prospective Clinical, Endoscopical, Pathological and Molecular Study.

Objective: to investigate the clinical, endoscopical, microscopical and molecular involvement of the GI tract in a prospective series of MCL.

Methods: 13 patients with MCL have been prospectively and consecutively entered in a staging workup that included upper and lower endoscopy of the GI tract. Multiple biopsies of the stomach and colon were taken from pathologic mucosa and also from macroscopically normal mucosa. Specimens were assessed with immunohistochemistry (IHC), FISH and PCR.

Results: Only 1 patient presented with GI symptoms at diagnosis. Endoscopy: Upper GI: abnormal mucosa in 5 cases (38%); Lower GI: abnormal mucosa in 6 cases (45%): mild colitis in 1, multiple micropolyps in 3, a large polyp and multiple micropolyps in 1 and three large polyps with normal mucosa in 1. As a whole, 9 patients (70%) had upper or lower endoscopic findings.

Pathology: 10 cases (77%) had microscopic infiltration by MCL of the upper GI tract and 10 cases (77%) of the lower GI tract. As a whole, all but one patient (92%) were found to have microscopic infiltration of the GI tract. All positive cases for CD20 and CD5 were positive for cyclin D1. The PCR product showed a clear monoclonal peak in 12 out of 19 samples, giving a sensitivity of 63.5% compared with IHC. FISH was positive in 7 out of 11 samples (sensitivity of 64% compared with IHC). All but one case with endoscopic abnormalities had GI microscopic infiltration by MCL and 67% of cases with normal endoscopy were found to have GI tract infiltration by MCL.

Conclusions: In our series, GI involvement by MCL was detected in almost all patients. All patients with endoscopic abnormalities had infiltration by MCL at the microscopic level. In 2/3 of the patients with normal endoscopy, GI tract involvement could be demonstrated at the microscopic level. IHC with cyclin D1 was more efficient than FISH and PCR as a diagnostic tool in this setting.