SEER Inquiry System - Question 20120029 Details

Code the primary site to main bronchus [C340].

Primary small cell carcinoma in the thymus/mediastinum is rare. A bronchial lesion with extension into the mediastinum is much more likely. In a case like this, it is difficult to be sure exactly where the tumor arose, however, it is recommended the default site be the main bronchus when there is no information to the contrary.