Pathology/Lab Coding Alert

Question: Our pathologist received a biopsy of a single pulmonary nodule from the patient’s right lower lung lobe. The final diagnosis is lung adenocarcinoma. What diagnosis code should we use? 

Texas Subscriber

Answer: You should use the final diagnosis in the pathology report. Based on the site and cancer diagnosis, you should report C34.31 (Malignant neoplasm of lower lobe, right bronchus or lung). 

Avoid: Don’t use the ordering diagnosis of R91.1 (Solitary pulmonary nodule).

Check specificity: ICD-10-CM provides many specific malignant lung-cancer codes based on anatomic site, so you should be familiar with the following options:

• C34.0- (Malignant neoplasm of main bronchus)
• C34.1- (… upper lobe, bronchus or lung)
• C34.2 (… middle lobe, bronchus or lung)
• C34.3- (… lower lobe, bronchus or lung)
• C34.8- (… overlapping sites of bronchus and lung)
• C34.9- (… unspecified part of bronchus or lung).

Next step: For all of the above codes except C34.2, you’ll need to delve deeper to determine an appropriate fifth digit to further specify the nodule location in the main bronchus or upper, middle, or lower lobe. For instance, if the malignant nodule biopsied was in the patient’s right bronchus, lower lobe, you’d report C34.31 (Malignant neoplasm of lower lobe, right bronchus or lung). For a malignant neoplasm in the patient’s right main bronchus, you’d choose C34.01 (Malignant neoplasm of right main bronchus).

If the neoplasm is in an unspecified part of the right lung, you’ll report C34.91 (Malignant neoplasm of unspecified part of right bronchus or lung).