C31Header code — not billable
Malignant neoplasm of accessory sinuses
- Chapter
- 2. Neoplasms
- Category
- C31
- Effective date
- October 1, 2026
Related codes in category C31
C31.0Malignant neoplasm of maxillary sinusYesC31.1Malignant neoplasm of ethmoidal sinusYesC31.2Malignant neoplasm of frontal sinusYesC31.3Malignant neoplasm of sphenoid sinusYesC31.8Malignant neoplasm of overlapping sites of accessory sinusesYesC31.9Malignant neoplasm of accessory sinus, unspecifiedYes
Frequently asked questions
What is ICD-10 code C31?
C31 is an ICD-10-CM diagnosis code for Malignant neoplasm of accessory sinuses.
Is C31 a billable code?
No. C31 is a category/header code, not billable on its own — use one of its more specific child codes instead.
What ICD-10-CM chapter is C31 in?
C31 falls under Chapter 2: Neoplasms.
When did C31 become effective?
C31 has been effective since October 1, 2026, per the CMS/CDC ICD-10-CM annual release.
What other codes are related to C31?
C31 belongs to category C31, which includes 6 other codes — see the related codes list on this page.
ICD-10-CM data maintained by CDC/CMS (public domain). Always verify codes with authoritative sources before making coding or billing decisions.