Treatment associated Mantle Cell Lymphoma with Cyclophosphamide therapy for Granulomatosis with Polyangiitis

We present a case of a 68-year-old woman who developed mantle cell lymphoma in the setting of long-term cyclophosphamide therapy and relapsing granulomatosis with polyangiitis (Wegener's granulomatosis, GPA). Adverse outcomes associated with cyclophosphamide therapy are well documented; however, the development of non-Hodgkin's lymphoma appears rare. Cumulative dose of cyclophosphamide (>36 g) is a significant risk factor in the development of serious long-term adverse outcomes and is particularly relevant to this case in which maintenance cyclophosphamide therapy was continued, following induction, for 2 years total, on account of patient preference. This case study will highlight the patient's initial diagnosis, treatment response, relapse and subsequent complications of therapy.