Multiple myeloma masquerading as medication-related osteonecrosis of the jaw: a case study

Abstract

Background Bisphosphonates, such as zoledronic acid, are commonly used to treat bone metastasis from malignant conditions, such as multiple myeloma, or from solid tumors, such as breast or prostate cancer. Medication-related osteonecrosis of the jaw (MRONJ) is one of the complications of bisphosphonate treatment. The reported incidence of MRONJ among patients with cancers and bone metastases treated with zoledronic acid is 1.3%. MRONJ has been reported to have an incidence rate of up to 18.5%. The clinical and radiographic presentations of MRONJ are very similar to those of bone metastases, making early diagnosis and timely treatment challenging. This is a case report of a patient with multiple myeloma with a history of treatment with zoledronic acid and whose initial presentation of an intraoral lesion made it challenging to distinguish between bone metastasis and MRONJ. Case Summary This is a case report of a 67-year-old female with multiple myeloma, with a history of zoledronic acid, 28 doses taken from 2013 to 2016 and the disease in remission. The patient initially presented with a 1-week history of firm gingival swelling buccal and lingual to a fixed partial denture (FPD) in the left mandible. Panoramic radiography showed a well-defined radiolucent lesion. Considering her history of antiresorptive treatment, MRONJ was considered as one of the diagnoses. However, because of the unusual hyperkeratotic nature of the buccal gingiva, relapsed disease was included in the differential diagnosis. Because of the unconventional clinical manifestation and concerns about relapsed disease, computed tomography guided bone biopsy was performed, and it revealed plasma cell neoplasm and necrotic bone. The patient was treated with palliative radiation therapy and antibiotics, which resulted in a significant decrease in her symptoms. Eventually, a portion of the FPD was removed, and an exposed bony site with a mobile bony sequestrum was revealed. Removal of the sequestrum led to complete gingival healing of the exposed site. Conclusions Maxillofacial manifestation of bone metastasis is common but is often overlooked. Therefore, it should be considered in the differential diagnosis when a patient with a history of antiresorptive medications presents with a gingival mass and/or exophytic bone. Good clinical judgment and well-timed bone biopsy and diagnostic imaging can lead to the correct diagnosis and optimal treatment.