Simultaneous osteodural and parasellar intracranial involvement as the initial presentation of multiple myeloma: A case report

Background Intracranial involvement in multiple myeloma (MM) is an uncommon manifestation that may create significant diagnostic challenges because of its radiological resemblance to more common intracranial tumors. Simultaneous involvement of multiple intracranial compartments at initial presentation is particularly unusual. Case description A 52-year-old female presented with a progressively enlarging frontoparietal mass, headaches, and a remote history of seizures. MRI demonstrated a 7.5 × 9.2 cm left parietal extra-axial lesion with contiguous calvarial and dural involvement and a second destructive lesion involving the clivus, sellar region, sphenoid sinus, and adjacent skull base. The parietal lesion was resected for decompression and tissue diagnosis. Histopathology demonstrated an IgG-kappa-restricted plasma-cell neoplasm (CD38+, CD138+, MUM1+, CD56+, kappa+, lambda−) with a Ki-67 index of 30–60%. Systemic evaluation showed anemia, IgG-kappa monoclonal gammopathy with an abnormal serum free-light-chain ratio, multiple osteolytic lesions, and < 10% bone marrow plasma cells. In the setting of a biopsy-proven plasma-cell neoplasm and multiple osteolytic lesions, the findings supported systemic MM rather than solitary plasmacytoma with minimal marrow involvement. The patient received bortezomib, lenalidomide, and dexamethasone with supportive filgrastim. Serum IgG decreased from 2470 to 902 mg/dL and the kappa/lambda ratio from 6.62 to 2.01. At 2-year follow-up, she remained neurologically stable and seizure-free, and the unresected parasellar lesion remained radiologically stable. Conclusion This case illustrates an unusual presentation of newly diagnosed MM with simultaneous osteodural and parasellar intracranial involvement. Such lesions may mimic other intracranial pathologies, particularly meningioma, potentially delaying diagnosis. Tissue diagnosis and comprehensive systemic evaluation are essential for distinguishing intracranial plasma-cell neoplasms from more common dural and skull-base tumors and for guiding multidisciplinary management.