Multiple myeloma invasion of the central nervous system.

Background: Although neurologic manifestations often complicate the course of patients with multiple myeloma (MM), direct central nervous system invasion is rare.

Objective: To describe the neurologic symptoms and signs, imaging, cerebrospinal fluid findings, and the clinical course of patients with central nervous system myeloma invasion, all of whom had leptomeningeal myelomatosis.

Design And Participants: Review of 23 patients with MM and leptomeningeal myelomatosis proven by malignant plasma cells in their cerebrospinal fluid.

Setting: Tertiary-care university medical center.

Results: Twenty-one patients had advanced-stage MM. Leptomeningeal myelomatosis was diagnosed up to 29 months (median, 13 months) after diagnosis of MM. Symptoms precipitating neurologic evaluation included manifestations of diffuse cerebral dysfunction, cranial nerve palsies, and spinal radiculopathies. Cerebrospinal fluid was abnormal in all patients, usually exhibiting pleocytosis and elevated protein content, plus positive cytologic findings. Specific magnetic resonance imaging findings suggestive of central nervous system invasion were found in 70% of the patients. These included leptomeningeal contrast enhancement and evidence of meningeal-based lesions sometimes masquerading as intraparenchymal lesions. Despite aggressive systemic and local treatment, the outcome was poor, reflecting the aggressiveness of the underlying MM.

Conclusion: Leptomeningeal myelomatosis, although rare, should be considered in patients with MM and symptoms suggestive of widespread nervous system involvement.