Neoplasm of uncertain behavior of pleura, thymus, and mediastinum

This code signifies the presence of a tumor in the pleura, thymus, or mediastinum whose biological behavior (benign vs. malignant) cannot be definitively determined from pathological examination. These neoplasms exhibit features that are neither clearly benign nor overtly malignant, requiring further investigation or observation.

Use this code when pathology reports indicate a neoplasm of uncertain behavior in the specified anatomical sites. This is appropriate when the pathologist cannot classify the tumor as benign or malignant based on current diagnostic criteria. Documentation must explicitly state "uncertain behavior" or "unknown behavior" for the neoplasm.

• Do not use this code if the neoplasm is definitively diagnosed as benign or malignant; use the appropriate code from categories 212 or 162/164.
• Ensure the documentation specifies the exact anatomical location (pleura, thymus, or mediastinum) to support this code.
• Consider sequencing this code as a primary diagnosis if the uncertain neoplasm is the reason for the encounter, or as a secondary diagnosis if it's an incidental finding being monitored.