Treatment outcomes of IgG4-producing marginal zone B-cell lymphoma: a retrospective case series.

IgG4-producing marginal zone B-cell lymphomas (MZLs) have been recently proposed as a subtype of MZLs. Despite the abundant literature on pathophysiological features of this type of lymphoma, only a few retrospective studies pertaining to the treatment outcomes have been reported, and its prognosis remains unclear. We retrospectively analyzed seven patients with IgG4-producing MZLs diagnosed at our institute, with specific reference to treatment and outcomes. The median age was 69.0 years (55-79), and all were males. The median follow-up period was 66.6 months (8-121). All patients had localized disease; four patients had tumors of the ocular adnexa, whereas two had retroperitoneal tumors. Five patients were treated with irradiation (30 Gy/15 fr) (n = 4) or surgery (n = 1), resulting in tumor reduction. Two patients were treated by chemotherapy or irradiation. Among them, one commenced rituximab monotherapy, which led to an inadequate reduction of the tumor. Subsequent irradiation induced complete response (CR). The other patient experienced repeated relapses during follow-up and finally achieved CR by combination chemotherapy. Treatment was well tolerated in all cases, and none of the patients showed disease progression at the last follow-up visit. Our results indicate that the standard treatments for MZLs are generally appropriate for IgG4-producing MZL.