Lung Anatomy and ICD-O-3

Priority order for coding primary site

  • ICD-O
  • SEER Program Coding Manual (Including Coding Guidelines in Appendix C)
  • Solid Tumor Rules (Lung)

NAACCR Item #400: Primary Site (#2580: Text-Primary Site Title)

ICD-O-3 Codes ICD-O-3 Preferred Term Synonyms Location
C340 Mainstem Bronchus: Bilateral
  • Bronchus intermedius
  • Carina
  • Hilus of lung
  • Perihilar
  • Starts at the trachea and extends only a few centimeters into the lung where it divides into secondary bronchi at the carina.

  • Bronchus intermedius is the portion of the right mainstem bronchus between
  • the upper lobar bronchus and the origin of the middle and lower lobar bronchi.

  • Carina is a ridge at the base of the trachea (windpipe) that separates the openings of the right and left main bronchi (the large air passages that lead from the trachea to the lungs).

  • The hilus is the area on the medial surface through which the main bronchus, pulmonary artery, pulmonary vein, nerves, and lymph vessels enter and leave each lung.
C341 Upper lobe lung: Left   Lingula of lung
C341 Upper lobe lung: Bilateral
  • Apex
  • Apex of lung
  • Lung apex
  • Pancoast tumor
  • Superior lobar bronchus
  • Upper lobe bronchi
  
C342 Middle Lobe: Right Middle lobe bronchi The left lung does not have a middle lobe. The heart is in the place of the middle lobe.
C343 Lower Lobe: Bilateral
  • Base of lung
  • Lower lobar bronchus
  • Lower lobe
  • Lower lobe bronchi
  • Lower lobe segmental
  • bronchi
  
C348 Overlapping lesion of lung: Bilateral   One lesion/tumor which overlaps two or more lobes.
C349 Lung NOS
  • Bronchus NOS
  • Bronchogenic
  • Extending up to the hilum
  • Extending down to the hilar region
  • Infrahilar NOS
  • Lung NOS
  • Pulmonary NOS
  • Suprahilar, NOS
 Includes
  • Multiple tumors in different lobes of ipsilateral lung
  • Multiple tumors in ipsilateral lung; unknown if same lobe or different lobe
  • Tumor in bronchus, unknown if mainstem or lobar bronchus
  • Tumor present, unknown which lobe
  • Multiple tumors abstracted as a single primary

Updated: April 8, 2026

Suggested Citation

SEER Training Modules: Lung Anatomy and ICD-O-3. U.S. National Institutes of Health, National Cancer Institute. Cited 12 April 2026. Available from: https://training.seer.cancer.gov.