Skull base osteomyelitis and bisphosphonate use in multiple myeloma: Report of two cases and literature review

Title: Skull Base Osteomyelitis and Bisphosphonate Use in Multiple Myeloma: Report of Two Cases and Literature Review Objectives: Although osteoradionecrosis of the mandible is a well known entity, skull base osteomyelitis involving the temporal bone unrelated to otitis externa in patients with multiple myeloma using bisphosphonates has not been reported. We described a new entity of skull base erosion resulting from osteonecrosis, presenting with malignant features in patients using bisphosphonates for multiple myeloma. Methods: Two patients with multiple myeloma and prior zolendronic acid use were referred to our cancer center for management of maxillary and temporal bone masses with skull base erosion. Both patients were in remission and not immunocompromised. Clinical symptoms included pain, cranial nerve deficits, and vertigo. An oroantral fistula developed in the maxillary patient. In both cases, repeat CT and MRI revealed an eroding mass consistent with malignancy. After repeated biopsies, however, no malignancy was seen, and pathology revealed chronic inflammation with bacterial colonization. Results: Imaging with technetium and gallium revealed osteomyelitis of the skull base in the temporal bone patient and actinomyces in the maxillary patient. Prolonged intravenous antibiotics resulted in significant improvement in symptoms andimaging after eight weeks of treatment. Conclusion: Bisphosphonate-associated osteomyelitis and necrosis of the mandible has been described in recent literature as a diagnostic and management dilemma. However, skull base osteomyelitis from the temporal bone has not been reported, and few cases from the maxilla have been reported. Early recognition and differentiation from similarly presenting malignant disease may prevent intracranial complications resulting from delayed treatment.