2018 ICD-10-CM Diagnosis Code C31.9

Malignant neoplasm of accessory sinus, unspecified

The following code(s) above C31.9 contain annotation back-references
Annotation Back-References
In this context, annotation back-references refer to codes that contain:
  • Applicable To annotations, or
  • Code Also annotations, or
  • Code First annotations, or
  • Excludes1 annotations, or
  • Excludes2 annotations, or
  • Includes annotations, or
  • Note annotations, or
  • Use Additional annotations
that may be applicable to C31.9:
  • C00-D49
    2018 ICD-10-CM Range C00-D49


    • Functional activity
    • All neoplasms are classified in this chapter, whether they are functionally active or not. An additional code from Chapter 4 may be used, to identify functional activity associated with any neoplasm.
    • Morphology [Histology]
    • Chapter 2 classifies neoplasms primarily by site (topography), with broad groupings for behavior, malignant, in situ, benign, etc. The Table of Neoplasms should be used to identify the correct topography code. In a few cases, such as for malignant melanoma and certain neuroendocrine tumors, the morphology (histologic type) is included in the category and codes.
    • Primary malignant neoplasms overlapping site boundaries
    • A primary malignant neoplasm that overlaps two or more contiguous (next to each other) sites should be classified to the subcategory/code .8 ('overlapping lesion'), unless the combination is specifically indexed elsewhere. For multiple neoplasms of the same site that are not contiguous, such as tumors in different quadrants of the same breast, codes for each site should be assigned.
    • Malignant neoplasm of ectopic tissue
    • Malignant neoplasms of ectopic tissue are to be coded to the site mentioned, e.g., ectopic pancreatic malignant neoplasms are coded to pancreas, unspecified (C25.9).
  • C30-C39
    2018 ICD-10-CM Range C30-C39

    Malignant neoplasms of respiratory and intrathoracic organs

    • malignant neoplasm of middle ear
    Type 1 Excludes
    Malignant neoplasms of respiratory and intrathoracic organs
Approximate Synonyms Clinical Information ICD-10-CM C31.9 is grouped within Diagnostic Related Group(s) (MS-DRG v35.0):

Convert C31.9 to ICD-9-CM

Code History
ICD-10-CM Codes Adjacent To C31.9
C26.9 Malignant neoplasm of ill-defined sites within the digestive system
C30 Malignant neoplasm of nasal cavity and middle ear
C30.0 Malignant neoplasm of nasal cavity
C30.1 Malignant neoplasm of middle ear
C31 Malignant neoplasm of accessory sinuses
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
C32 Malignant neoplasm of larynx
C32.0 Malignant neoplasm of glottis
C32.1 Malignant neoplasm of supraglottis
C32.2 Malignant neoplasm of subglottis
C32.3 Malignant neoplasm of laryngeal cartilage
C32.8 Malignant neoplasm of overlapping sites of larynx
C32.9 Malignant neoplasm of larynx, unspecified
C33 Malignant neoplasm of trachea
C34 Malignant neoplasm of bronchus and lung
C34.0 Malignant neoplasm of main bronchus

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.