Neoplasm of uncertain behavior of left breast

This code signifies a tumor in the left breast where the pathologist cannot definitively determine if it is benign or malignant based on current microscopic examination. It represents an abnormal growth with features that are intermediate between benign and malignant, requiring further investigation or monitoring.

Apply this code when pathology reports describe a breast lesion as "uncertain behavior," "borderline," "atypical," or "of undetermined malignant potential" specifically located in the left breast. Documentation must clearly indicate the left laterality and the pathologist's inability to classify the neoplasm as definitively benign or malignant.

• Ensure the documentation explicitly states "left breast" to support laterality.
• Do not use this code if the pathology definitively classifies the neoplasm as benign (e.g., fibroadenoma) or malignant (e.g., invasive ductal carcinoma).
• Sequence this code as the primary diagnosis when the neoplasm of uncertain behavior is the reason for the encounter.