ICD-10 Code D43.8 – Neoplasm of uncertain behavior of other specified parts of central nervous system (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D43.8 – Neoplasm of uncertain behavior of other specified parts of central nervous system
What it is
This code identifies a neoplasm in a specified central nervous system site where the pathologist or clinician cannot determine whether it is benign or malignant. Use it when the documentation names an “uncertain behavior” tumor in another specified CNS location.
Clinical signs
Clinical features vary; refer to documentation. Patients may have neurologic deficits, seizures, headaches, or focal symptoms related to the tumor’s location, but the code itself is based on the documented diagnosis, not symptom pattern.
When to use this code
Use D43.8 when the record clearly states a neoplasm of uncertain behavior in a specified central nervous system site other than the sites covered by more specific codes. It is appropriate when the provider documents uncertain biologic behavior and the location is identified. If the site or behavior is unclear, check documentation.
Do not use for
Do not use this code for benign, malignant, or metastatic CNS tumors, or when the record does not specify uncertain behavior. If the anatomic site is better described by a more specific code, use that code instead.
Coding tip
Confirm both the “uncertain behavior” wording and the exact CNS site before assigning D43.8.