Osteopetrosis, a potential mimicker of sclerotic metastatic bone lesions in breast cancer

Abstract Bone is the most common site of metastasis in breast cancer. Metastatic bone disease mimickers occur and some of have been defined previously. They can lead to unnecessary biopsies, improper or delayed therapy, and patient anxiety. Here we report on a patient with a history of osteopetrosis, a sclerotic bone disease, who developed breast cancer. Following treatment of breast cancer her osteopetrosis was confused for metastatic bone disease three times on imaging studies due to the lack of proper clinical history offered to the radiologist prior to the interpretation of the exams. Various discrete and generalized bone conditions that can mimic bone metastasis in breast cancer have been reported. Discrete conditions include vertebral osteomyelitis, brown fat, osteopoikilosis, and myositis ossificans. Generalized conditions include mastocytosis and now osteopetrosis. Other sclerotic bone disorders may potentially be confused with metastatic disease to bone. A list of the more common examples with characteristic radiographic features is presented. Considering a patient's past medical history including sclerosing bone disorders and prior imaging findings when interpreting new imaging studies can help reduce unnecessary confusion. Patients with sclerosing bone disease should be counseled to inform ordering and interpreting physicians about potential misinterpretation.