Malignant neoplasm of meninges (C70) ICD-10-CM
The C70 code range covers malignant neoplasm of meninges with 4 ICD-10-CM diagnosis codes. 3 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Codes in the C70 Range 4 codes · 3 billable
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the C70 range.
Arachnoid
A delicate membrane enveloping the brain and spinal cord. It lies between the PIA MATER and the DURA MATER. It is separated from the pia mater by the subarachnoid cavity which is filled with CEREBROSPINAL FLUID.
Arachnoid Cysts
Intracranial or spinal cavities containing a cerebrospinal-like fluid, the wall of which is composed of arachnoidal cells. They are most often developmental or related to trauma. Intracranial arachnoid cysts usually occur adjacent to arachnoidal cistern and may present with HYDROCEPHALUS; HEADACHE; SEIZURES; and focal neurologic signs. (From Joynt, Clinical Neurology, 1994, Ch44, pp105-115)
Arachnoiditis
Acute or chronic inflammation of the arachnoid membrane of the meninges most often involving the spinal cord or base of the brain. This term generally refers to a persistent inflammatory process characterized by thickening of the ARACHNOID membrane and dural adhesions. Associated conditions include prior surgery, infections, trauma, SUBARACHNOID HEMORRHAGE, and chemical irritation. Clinical features vary with the site of inflammation, but include cranial neuropathies, radiculopathies, and myelopathies. (From Joynt, Clinical Neurology, 1997, Ch48, p25)
Medulloblastoma
A malignant neoplasm that may be classified either as a glioma or as a primitive neuroectodermal tumor of childhood (see NEUROECTODERMAL TUMOR, PRIMITIVE). The tumor occurs most frequently in the first decade of life with the most typical location being the cerebellar vermis. Histologic features include a high degree of cellularity, frequent mitotic figures, and a tendency for the cells to organize into sheets or form rosettes. Medulloblastoma have a high propensity to spread throughout the craniospinal intradural axis. (From DeVita et al., Cancer: Principles and Practice of Oncology, 5th ed, pp2060-1)
Meninges
The three membranes that cover the BRAIN and the SPINAL CORD. They are the dura mater, the arachnoid, and the pia mater.
Meningocele
A congenital or acquired protrusion of the meninges, unaccompanied by neural tissue, through a bony defect in the skull or vertebral column.
Pia Mater
The innermost layer of the three meninges covering the brain and spinal cord. It is the fine vascular membrane that lies under the ARACHNOID and the DURA MATER.
About the C70 Code Range
The ICD-10 code C70 and its extensions are used to classify malignant tumors originating in the meninges, which are the protective layers surrounding the brain and spinal cord. These codes specify whether the cancer affects cerebral, spinal, or unspecified meninges.
Specifically, C70.0 denotes a malignant neoplasm of the cerebral meninges, including tumors known as primary malignant meningiomas or malignant meningiomas of the optic nerve sheath. This category covers cancers arising from the dura mater, arachnoid mater, or pia mater of the brain's meninges. The C70.1 code is used when the malignant neoplasm affects the spinal meninges, involving the dura, arachnoid, or pia mater layers of the spinal cord's protective tissues. For cases where the exact meninges location is not specified, C70.9 captures malignant neoplasms of meninges without further detail and includes terms like malignant melanoma of the meninges or metastatic malignant neoplasm of meninges. These codes help coders and clinicians accurately identify and document primary malignant meningeal tumors for treatment and billing purposes, guiding diagnosis and management of aggressive nervous system cancers.
Questions About This Page
How many billable codes are in the C70 range?
Of the 4 codes in this range, 3 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the C70 range classify?
The range classifies malignant neoplasm of meninges. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
