Treatment associated M antle C ell L ymphoma 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 ( W egener's granulomatosis, GPA ). Adverse outcomes associated with cyclophosphamide therapy are well documented; however, the development of non‐ H odgkin'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.