D33.1

HCC Category Mapping

What This Code Means

A non-cancerous tumor located in the lower portion of the brain below the tentorium cerebelli, including the cerebellum and brainstem.

Coding Tips

• •Infratentorial tumors are located below the tentorium; ensure this distinction is documented
• •These tumors may present with different symptoms than supratentorial tumors due to their location

Clinical Significance

Benign neoplasm of the infratentorial brain encompasses benign tumors below the tentorium cerebelli, primarily in the posterior fossa including the cerebellum, brainstem, and fourth ventricle. Common benign infratentorial tumors include pilocytic astrocytomas, hemangioblastomas, and epidermoid cysts. These tumors can cause hydrocephalus, cerebellar dysfunction, and cranial nerve palsies due to the confined posterior fossa anatomy.

Documentation Requirements

• ✓MRI brain documenting the posterior fossa tumor location with imaging characteristics.
• ✓If resected, pathology must confirm benign histology.
• ✓Document the specific infratentorial location (cerebellum, brainstem, fourth ventricle), tumor size, degree of hydrocephalus if present, and neurological examination findings.
• ✓Include treatment plan and surveillance schedule.

Commonly Confused Codes