You don't need separate diagnoses but should code more specifically regarding tumor site.
There are four main types of lung cancer, categorized by how the cancerous cells appear under a microscope:
- Small cell lung cancer (SCLC), also called oat cell cancer (SCLC spreads rapidly and is more likely than other types to have metastasized)
- Squamous cell carcinoma, also called epidermoid carcinoma
- Adenocarcinoma, which is likely to spread to lymph nodes and other organs
- Large cell carcinoma, which includes cells that are not diagnosed as squamous, adenocarcinoma, or SCLC.
Regardless of the cell type, you code primary malignant neoplasm of the lung as 162.x, with the fourth-digit subcategory identifying the specified site of the cancer:
- 162.0 -- Malignant neoplasm of trachea, bronchus, and lung; trachea
- 162.2 -- - main bronchus
- 162.3 -- - upper lobe, bronchus, or lung
- 162.4 -- - middle lobe, bronchus, or lung
- 162.5 -- - lower lobe, bronchus, or lung
- 162.8 -- - other parts of bronchus or lung (This includes malignant neoplasm of contiguous or overlapping sites of bronchus or lung whose point of origin cannot be determined.)
- 162.9 -- - bronchus and lung, unspecified.
Carcinoma in situ of the lung merits diagnosis code 231.2 (Carcinoma in situ of respiratory system; bronchus and lung).
Once you code the site, you also need to consider the nonmalignant neoplasm's behavior and report it accordingly. Nonmalignant neoplasms of the lung fall into three classifications:
- 212.3 -- Benign neoplasm of respiratory and intrathoracic organs; bronchus and lung
- 235.7 -- Neoplasm of uncertain behavior of digestive and respiratory systems; trachea, bronchus, and lung
- 239.1 -- Neoplasm of unspecified nature; respiratory system.
If the lung cancer is considered a metastatic site -- in other words, if the cancer spread from another organ to the lung -- you-ll code 197.0 (Secondary malignant neoplasm of respiratory and digestive system; lung).
Bottom line: Reporting the correct diagnosis for NSCL or SCLC is more involved than simply assigning 162.9. Check all documentation for the details you need to select the best code.