Malignant neoplasm of axillary tail of right female breast

This code identifies a primary cancerous tumor originating in the axillary tail (tail of Spence) of a female patient's right breast. This specific anatomical location is an extension of the breast tissue into the axilla. The neoplasm is confirmed to be malignant, indicating invasive or potentially invasive cellular growth.

This code is appropriate when documentation clearly specifies a primary malignant neoplasm located in the axillary tail of the right female breast. Supporting documentation would include pathology reports confirming malignancy and operative reports or imaging studies detailing the tumor's precise location within the axillary tail.

• Ensure the laterality (right) and patient's sex (female) are explicitly documented.
• Distinguish from malignant neoplasms of other specified or unspecified parts of the breast (C50.8xx, C50.9xx).
• Confirm this is a primary malignancy; use secondary codes (C79.81) for metastatic disease to the breast.