Paraneoplastic Necrotizing Myopathy Post Lumpectomy and Chemotherapy for Early Breast Cancer

Our case report describes a 60-year-old female patient with a past medical history of Stage IB breast cancer, status post lumpectomy and adjuvant chemotherapy, admitted to our hospital with the chief complaints of fever, myalgia, and muscle weakness. A physical exam revealed proximal muscle weakness and a facial rash. A full workup was done, and the muscle biopsy showed evidence of a necrotizing myopathic process, which confirmed our diagnosis. This led to a diagnosis of necrotizing myopathy, deemed to be paraneoplastic after other possible differentials were ruled out. The patient showed improvement after a five-day course of intravenous immunoglobulin (IVIG) and high-dose steroids. Necrotizing myopathy, as a paraneoplastic process, has been scarcely described. In the context of our case, we review the characteristics and relevant existing literature about paraneoplastic necrotizing myopathy as well as emphasize the need to include it as a differential in the setting of malignancy.