We describe a case of multicentric Castleman disease with generalized lymphadenopathy and splenomegaly, accompanied by typical B symptoms - loss of 15 kg, fever of non-infectious origin, night sweats, symptoms of anemia. Histological examination of the nodes with the highest accumulation of fluorodeoxyglucose, taken from mediastinum by thoracoscopy, revealed plasmocellular type of Castleman disease. Tests for HIV and human herpesvirus 8 (HHV-8) were negative. Three recurrences of herpes zoster indicating an alteration of immunity preceded the dia-gnosis of disease. Treatment was initiated with combination of thalidomide, dexamethasone, and cyclophosphamide. The response after 2 months therapy was not clear and patient doesn't tolerated the therapy well. Therefore, this treatment was terminated and R-CHOP (Mabthera - rituximab, cyclophosphamide, adriamycin, vincristine, and prednisone) was selected as a second-line therapy. Lymphadenopathy and splenomegaly were reduced during the 2 cycles of treatment, however, serious infectious complications accompanied the therapy. Therefore, only use of Mabthera monotherapy 375 mg /m2 was administered in 28-day intervals. This treatment has shown efficacy and tolerability. PET-CT scan has demonstrated disappearance of lymphadenopathy and splenomegaly, in addition, normalized accumulation of fluorodeoxyglucose. Monotherapy with Mabthera has proved to be effective and well tolerated drug in this case. Currently, there are more effective therapeutic alternatives in multicentric Castleman disease: treatment with monotherapy of rituximab or in combination therapy with immunomodulatory drugs (thalidomide or lenalidomide, treatment with anti-IL-6 (siltuximab) or against its receptor (tocilizumab). In the case of ineffectiveness of one treatment option must be tested other alternative. In this case the therapy based on thalidomide wasn't successful, whereas the treatment with Mabthera has achieved disappearance of disease symptoms.