Multiple myeloma presenting as left-sided weakness: a case report

Introduction: Left-sided weakness, as well as other neurologic symptoms, from multiple myeloma happens only in 5% of cases.

Presentation of Case: A 61-year old female presented with progressive left-sided weakness for 2 months. MRI showed lytic lesions on the ribs, scapula and spine comparable to metastatic lesions. A cranial CT scan revealed a mass on the right frontotemporal area. Surgical resection was done and histopathology showed Kappa Light Chain Restricted Plasma Cell Myeloma. Further immunohistochemical investigation showed positive to LCA, MUM-1, CD138, and Kappa.  Stain was negative to CK, CD3, CD20, EBER, and Lambda. Bone marrow core biopsy and aspirate showed plasma cell myeloma (59.4% plasmacytosis) and grade I reticulin fribrosis.

Discussion: Most patients with multiple myeloma manifest with symptoms that point to infiltration of plasma cells into the organs of the body. The presence of neurological symptoms is a rare presentation of plasmacytoma, with the incidence of central nervous system (CNS) involvement in multiple myeloma being 1%. Cord compression and stroke are the most common neurologic complication of multiple myeloma.

Conclusion: Neurologic symptoms may be seen in multiple myeloma, though a wide range of etiology must be considered.  Intracranial plasmacytomas are rare and usually manifest later in the disease progression.