Malignant Melanoma of Meninges; Meningeal Melanomatosis – Diffuse Type - Primary Intracranial Malignant Melanoma; Primary CNS Melanoma; Primary Intracranial Leptomeningeal Melanomatosis; Primary Intracranial Melanocytic Neoplasm; Primary Leptomeningeal Melanoma; Primary Melanocytic Tumor; Primary Melanoma of the Central Nervous System; Primary Melanoma of the Meninges

Primary intracranial malignant melanoma (PIMM) is an extremely rare, aggressive brain malignancy that emerges from the melanocytes lining tissue that surrounds the brain and spinal cord. PIMM lacks specific symptoms and often mimics meningioma on imaging. They are like melanomas of other sites and are diagnosed after melanoma brain metastases have been ruled out. It accounts for approximately 1% of all melanomas and 0.07% of all brain malignancies. PIMM rarely spreads beyond the central nervous system (CNS).

Diagnostic testing: The diagnosis of PIMM is made by:

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  Cerebrospinal fluid cytopathology;

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  Dermatological skin exam;

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  Eye examination;

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  Full-body screening;

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  Histopathology;

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  Magnetic resonance imaging (MRI)/computed tomography (CT);

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  Pathology reports; and

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  Surgical tissue biopsy.

Physical findings:

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  Raised intracranial pressure;

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  Headaches;

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  Focal neurological symptoms related to tumor location;

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  Seizures or subarachnoid hemorrhage;

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  Spinal tumor;

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  Back pain;

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  Muscle weakness;

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  Numbness;

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  Plegia (a kind of paralysis); and

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  Urinary incontinence.

ICD-9: 191.0-191.9; 192.1

ICD-10: C70.9

PIMM is highly aggressive, infiltrating, and responds poorly to treatments. The prognosis is poor due to high recurrence, with an average survival of 23 months with a three-year survival rate of only 13%.

Treatment of PIMM consists of a combination of surgical resection, adjuvant (post-surgical) radiation, and chemotherapy. Targeted immunotherapy may also be used.

Suggested MER for Evaluation:

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  Clinical history and examination that describes the diagnostic features of the impairment;

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  Pathology reports of the cancer biopsy or surgical specimen are the critical information necessary for disability evaluation;

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  Operative reports; and

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  Results of neuroimaging (e.g. CT, MRI).

Suggested Listings for Evaluation:

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13.29C