The antineoplastic drug, bendamustine hydrochloride, combines the 2-chlorethylamine group of the nitrogen mustard derived alkylating agents with the benzimidazole ring structures of the purine analogue. Bendamustine has been shown to be highly active in a variety of lymphoproliferative disorders. The combination of bendamustine and rituximab has produced high overall and complete response rates and prolonged remissions with only moderate and manageable toxicity in Waldenström's macroglobulinemia, which is closely related to primary CAD. In an attempt to improve on the therapeutic efficacy achieved with the rituximab-based regimens and the toxicity profile of the fludarabine-rituximab combination, the investigators want to study the safety and efficacy of bendamustine and rituximab combination therapy in patients with primary CAD.