ICD-10 Code D42.9 – Neoplasm of uncertain behavior of meninges, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D42.9 – Neoplasm of uncertain behavior of meninges, unspecified
What it is
This code identifies a meningeal tumor whose behavior is uncertain, meaning the pathology does not clearly show benign or malignant behavior. Use it when the site is the meninges and the record does not specify a more exact location.
Clinical signs
Clinical features vary; refer to documentation. Patients may have findings related to a mass effect or incidental imaging discovery, but the diagnosis should be supported by pathology or specialist assessment.
When to use this code
Use D42.9 when the provider documents a neoplasm of uncertain behavior involving the meninges and does not identify a more specific meningeal site. It also fits when the lesion is described as uncertain or borderline and no malignant diagnosis is recorded. Check documentation if the pathology report is incomplete.
Do not use for
Do not use this code for clearly benign meningeal tumors or for malignant neoplasms of the meninges. If the record names a specific meningeal site, code that more exact option instead.
Coding tip
Confirm both the anatomic site and the behavior wording in the pathology or provider note before assigning D42.9.