Neoplasm of uncertain behavior of unspecified breast

This code signifies a breast lesion where the pathologist cannot definitively classify it as benign or malignant based on current microscopic examination. It indicates an abnormal growth with features that are intermediate between clearly benign and clearly cancerous, requiring further investigation or monitoring.

Apply this code when pathology reports describe a breast neoplasm as "uncertain behavior," "of unknown malignant potential," or similar terminology, and the specific breast quadrant or laterality is not documented. This is often an interim diagnosis pending further workup, such as additional biopsies or genetic testing.

• Do not use this code if the pathology definitively states benign or malignant; instead, code to the specific benign or malignant neoplasm.
• If laterality (left, right) or specific quadrant is documented, use the more specific D48.61 or D48.62 codes.
• Always review the final pathology report. If a definitive diagnosis is made, update the code accordingly.