ICD-10 Code C70.9 – Malignant neoplasm of meninges, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C70.9 – Malignant neoplasm of meninges, unspecified
What it is
C70.9 identifies a malignant tumor arising in the meninges, the protective membranes around the brain and spinal cord, when the exact meningeal site is not specified. Use this code when documentation confirms malignancy but does not name a more specific meningeal location.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include neurologic symptoms related to mass effect or irritation, but the record should support a malignant meningeal neoplasm rather than another CNS condition.
When to use this code
Use C70.9 when the provider documents a malignant neoplasm of the meninges and does not specify whether it is cranial or spinal. It also fits when the site is noted only as “meninges” or “meningeal malignancy.” If a more specific meningeal site is documented, code that instead.
Do not use for
Do not use this code for benign meningeal tumors, metastatic disease to the meninges, or non-malignant meningeal conditions. Check documentation if the lesion is described as uncertain, secondary, or arising elsewhere.
Coding tip
Query for the exact meningeal site when the note is vague, because C70.9 is reserved for unspecified location.