Immunophenotypic profiles for distinguishing orbital mucosa-associated lymphoid tissue lymphoma from benign lymphoproliferative tumors.

Purpose: To evaluate novel immunophenotypic profiles of patients with orbital lymphoproliferative tumors.

Methods: From 2006 to 2014, surgical biopsies from consecutive patients with newly diagnosed orbital mucosa-associated lymphoid tissue (MALT) lymphoma and IgG4-related ophthalmic disease (IgG4-ROD) were collected from Tokyo Medical University Hospital. A total of 44 tumors from 44 patients were analyzed, including 21 with orbital MALT lymphoma (11 men and 10 women, mean age 67.8 ± 13.4 years) and 23 with definitive IgG4-ROD (9 men and 14 women, mean age 60.5 ± 15.1 years). Patients with secondary orbital MALT lymphoma and MALT lymphoma with IgG4-ROD were excluded. All patients were immunocompetent Asian adults. Samples were analyzed by immunohistochemistry and flow cytometric analysis. Flow cytometry was performed with the following antibodies: CD3, CD4, CD5, CD8, CD10, CD19, CD20, CD23, CD25, CD30, CD34, and CD56 lambda and kappa chains.

Results: Expression of CD25 and CD19 was higher in patients with orbital MALT lymphoma compared to patients with IgG4-ROD (p < 0.001). In contrast, expression of CD3, CD4, and CD23 was higher in patients with orbital IgG4-ROD compared to those with MALT lymphoma (all p < 0.01). The presence of CD23 and CD25 in the specimens was confirmed by immunohistochemistry.

Conclusion: The present study elucidated the novel immunophenotypic features of orbital MALT and benign lymphoproliferative disorders such as IgG4-ROD. Among them, CD23 and CD25 have shown a disease-specific expression pattern.