Neoplasm of uncertain behavior of left renal pelvis

This code signifies a tumor originating in the left renal pelvis that pathologists have determined cannot be definitively classified as benign or malignant based on current microscopic examination. It indicates an abnormal growth with features that are ambiguous, requiring further investigation or monitoring to determine its true biological nature.

Apply this code when pathology reports describe a neoplasm of the left renal pelvis as "uncertain behavior," "borderline," or "of unknown malignant potential." Documentation must clearly specify the left side and the renal pelvis as the tumor's origin, along with the pathologist's assessment of uncertain behavior.

• Ensure the laterality (left) and specific anatomical site (renal pelvis) are explicitly documented.
• Distinguish carefully from benign neoplasms (D30.0-) or malignant neoplasms (C64.1) of the kidney and renal pelvis.
• This code often necessitates further diagnostic workup or close surveillance due to its indeterminate nature.