Leptomeningeal Carcinomatosis Differential Diagnoses

Updated: Nov 27, 2017
  • Author: Michael J Schneck, MD, MBA; Chief Editor: Stephen A Berman, MD, PhD, MBA  more...
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Diagnostic Considerations

New signs or symptoms may represent leptomeningeal carcinomatosis (LC) progression, but must be distinguished from parenchymal disease, because 30-40% of those with LC also have brain metastases also, paraneoplastic syndromes, or the adverse effects of chemotherapy or radiation. Multifocal neurologic signs can also be characteristic signs of multiple brain or epidural metastases, and signs of meningeal irritation can also be caused by infection.

LC can be difficult to distinguish from subacute or chronic meningoencephalitis caused by tuberculosis or fungus, as CSF findings in both show moderate mononuclear pleocytosis and decreased glucose. However, patients with LC usually are afebrile, and their neurologic symptoms appear early in the course with a preserved level of consciousness, rather than late with depressed mental status as in tubercular or fungal meningoencephalitis.

Intradural extramedullary spinal metastases (IESM) may be a separate phenomenon from LC. Proposed diagnostic criteria for IESM include: solid tumors located within the intradural extramedullary space, the absence of other leptomeningeal lesions seen on full-spine injected magnetic resonance imaging, and the absence of malignant cells in cerebrospinal fluid. According to one study, the median overall survival was significantly higher for IESM patients (732 days) than for patients with LC (53 days). [35]

Differential Diagnoses