C31.9 – Malignant neoplasm of accessory sinus, unspecified
ICD-10-CM 2027 diagnosis code · Malignant neoplasms of respiratory and intrathoracic organs
ICD-10-CM code
C31.9
- Code
C31.9(claims format:C319)- Description
- Malignant neoplasm of accessory sinus, unspecified
- Billable
- Yes – valid for HIPAA-covered transactions
- Valid for
- Dates of service October 1, 2026 – September 30, 2027 (FY2027)
- Chapter
- 2. Neoplasms (C00-D49)
- Block
- C30-C39 Malignant neoplasms of respiratory and intrathoracic organs
- Parent codes
- C31
Notes inherited from parent codes
Instructional notes at a category or block level apply to every code below it.
Block C30-C39
Includes:
- malignant neoplasm of middle ear
Excludes1 (not coded here):
- mesothelioma (C45.-)
Related codes in C31
Frequently asked questions
What is ICD-10 code C31.9?
C31.9 is the ICD-10-CM code for malignant neoplasm of accessory sinus, unspecified, in the block C30-C39 (Malignant neoplasms of respiratory and intrathoracic organs).
Is C31.9 a billable code?
Yes. C31.9 is a billable/specific code that can be used to indicate a diagnosis for reimbursement purposes.
What category does C31.9 belong to?
It belongs to category C31 – Malignant neoplasm of accessory sinuses.
Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.