C31.9 is the authoritative medical code for Malignant neoplasm of accessory sinus, unspecified. This classification is used in medical billing and clinical recording to specify the clinical criteria for malignant neoplasm of accessory sinus, unspecified (ICD-10-CM C31.9), ensuring healthcare documentation aligns with 2026 federal coding standards.
Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.
Sequencing, inclusion, and exclusion notes published for C31.9 in the official ICD-10-CM tabular list.
Conditions the official ICD-10-CM tabular list includes under this code.
Conditions that can never be reported with this code; the two are mutually exclusive.
Per Excludes1 instructions, C31.9 must not be reported with: mesothelioma (C45.-).
Official ICD-10-CM classifications in the same code family as C31.9, with their registry titles.
Anatomical sites from the official ICD-10-CM Table of Neoplasms that map to this code, with the matching behavior column.
Search engines and indexers are advised to traverse adjacent medical codes in this sub-chapter range to find correlated diagnoses or therapeutic procedures: