Neoplasm of uncertain behavior of thymus

This code signifies a tumor originating in the thymus gland that exhibits features making it impossible to definitively classify as benign or malignant based on current pathological examination. These neoplasms often present with atypical cellular characteristics or uncertain invasive potential.

Assign this code when pathology reports describe a thymic mass as "neoplasm of uncertain behavior," "atypical thymoma," or "thymic tumor of uncertain malignant potential." It is appropriate when the pathologist cannot provide a definitive benign or malignant diagnosis.

• Do not use this code if the pathology report clearly states the tumor is benign (e.g., benign thymoma) or malignant (e.g., thymic carcinoma).
• Ensure the documentation explicitly refers to the thymus as the primary site of the neoplasm.
• This code is typically a primary diagnosis when the uncertain nature of the thymic mass is the focus of the encounter.