C79.31 Secondary malignant neoplasm of brain

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applies from C79 Secondary malignant neoplasm of other and unspecified sites

Excludes1 (never code together)

• secondary carcinoid tumors (C7B.-)
• secondary neuroendocrine tumors (C7B.-)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 17 — Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic
• CMS-HCC V22: HCC 8 — Metastatic Cancer and Acute Leukemia
• RxHCC V08: HCC 18 — Secondary Cancer of Lung, Liver, Brain, and Other Sites
• ESRD V24: HCC 8

MS-DRG index

Defines the logic of DRG(s) 054-055 in MDC 01.

Approximate ICD-9-CM (GEMs)

• 198.3 Secondary malignant neoplasm of brain and spinal cord (approximate)

Nearby codes

• C79.10 Secondary malignant neoplasm of unspecified urinary organs
• C79.11 Secondary malignant neoplasm of bladder
• C79.19 Secondary malignant neoplasm of other urinary organs
• C79.2 Secondary malignant neoplasm of skin
• C79.3 Secondary malignant neoplasm of brain and cerebral meninges
• C79.31 Secondary malignant neoplasm of brain (this code)
• C79.32 Secondary malignant neoplasm of cerebral meninges
• C79.4 Secondary malignant neoplasm of other and unspecified parts of nervous system
• C79.40 Secondary malignant neoplasm of unspecified part of nervous system
• C79.49 Secondary malignant neoplasm of other parts of nervous system
• C79.5 Secondary malignant neoplasm of bone and bone marrow