ICD-10 Code D43 – Neoplasm of uncertain behavior of brain and central nervous system (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D43 – Neoplasm of uncertain behavior of brain and central nervous system
What it is
D43 identifies a tumor of the brain or central nervous system whose behavior is uncertain. Use it when records describe a neoplasm that cannot yet be classified as benign or malignant.
Clinical signs
Clinical features vary; refer to documentation. Patients may have neurologic findings related to the tumor’s location, such as headache, seizures, focal deficits, or signs of increased intracranial pressure.
When to use this code
Use D43 when the provider documents an uncertain-behavior neoplasm involving the brain, spinal cord, meninges, or related central nervous system structures. It is appropriate for pathology or imaging reports that do not establish benign or malignant behavior. If the site or behavior is later clarified, update the code accordingly.
Do not use for
Do not use D43 for clearly benign or malignant CNS tumors, or for metastatic disease to the brain. Check documentation if the report names a specific histology or a more definite behavior.
Coding tip
Capture the exact anatomic site and wait for final pathology when behavior is not yet confirmed.