Treatment of Extranodal Marginal Zone Lymphoma and Primary Cutaneous B Cell Lymphoma with Rituximab: A Single Institution Experience.

Extranodal marginal zone lymphoma is a low grade B cell lymphoma. It comprises about 5% of all non-hodgkin’s lymphoma. They typically present in the lung, thyroid, breast, lacrimal and salivary gland, orbit, and skin. Primary cutaneous B cell lymphoma is an extremely rare form of lymphoma with 3 histological variants: marginal zone, follicular, and diffuse large B cell. In general, they have a high remission rate with overall survival up to 80% at 10 years. At the University of Colorado Health Sciences Center, we have seen ten such cases from July 2005 to July 2007. There is no standard treatement for either extranodal marginal zone lymphoma or primary cutaneous B cell lymphoma, but prior reports have shown long term survival with surgery, radiation, and chemotherapy. Most institutions use radiation therapy as the main modality after excisional biopsy. There is one report by Gitelson et al (leuk lymphoma 2006) using single agent rituximab as the only modality. Out of the ten cases at our institution, six cases were primary cutaneous B cell lymphoma (4 marginal zone, 1 follicular, one diffuse large B cell), and four cases were extranodal marginal zone lymphoma. Four out of six cases of primary cutaneous B cell lymphoma and three out of four of extranodal marginal zone lymphoma was treated with single agent rituximab. Two out of the six cases of primary cutaneous B cell lymphoma and one out of four of extranodal marginal zone lymphoma was treated with radiation. Patients were given induction therapy rituximab at the dose of 375mg/m2 IV weekly x 4 weeks and maintenance therapy at 375 mg/m2 IV every two to three month interval for 8 cycles. 7 patients were given rituximab single agent. All achieved CR (100%) immediately after induction therapy at 1 month. They were also given maintenance treatment. No relapses has occured at the medium follow up of 7 month (3–24 month). Our preliminary result supports the recent report of single agent rituximab. Even though extranodal marginal zone lymphoma is a rare disorder and primary cutaneous B cell lymphoma even more rarer, we feel that a well designed prospective randomized trial would determine the role of rituximab for this disease.