C31.9 Malignant neoplasm of accessory sinus, unspecified

Billable ICD-10-CM code, FY2026.

Risk adjustment (HCC)

• CMS-HCC V28: HCC 21 — Lymphoma and Other Cancers
• CMS-HCC V22: HCC 11 — Colorectal, Bladder, and Other Cancers
• RxHCC V08: HCC 22 — Prostate, Breast, Bladder, and Other Cancers and Tumors
• ESRD V24: HCC 11

MS-DRG index

Defines the logic of DRG(s) 011-013 in MDC PRE.

Approximate ICD-9-CM (GEMs)

• 160.9 Malignant neoplasm of accessory sinus, unspecified

Nearby codes

• C31.0 Malignant neoplasm of maxillary sinus
• C31.1 Malignant neoplasm of ethmoidal sinus
• C31.2 Malignant neoplasm of frontal sinus
• C31.3 Malignant neoplasm of sphenoid sinus
• C31.8 Malignant neoplasm of overlapping sites of accessory sinuses
• C31.9 Malignant neoplasm of accessory sinus, unspecified (this code)