ICD-10 Code C50.819 – Malignant neoplasm of overlapping sites of unspecified female breast (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C50.819 – Malignant neoplasm of overlapping sites of unspecified female breast
What it is
C50.819 identifies a malignant breast tumor in a female patient when the cancer spans overlapping sites within the breast and the side is not specified. Use it when documentation confirms breast cancer but does not name a more specific overlapping location.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include a breast mass, skin or nipple changes, or abnormal imaging that leads to biopsy-confirmed malignancy.
When to use this code
Use this code when the record states malignant neoplasm of overlapping breast sites in an unspecified female breast and no laterality is documented. It is appropriate for confirmed breast cancer cases where the provider does not identify a single anatomic subsite. Check documentation if the note later specifies left or right breast, or a different breast quadrant.
Do not use for
Do not use this code for benign breast lesions, in situ disease, or malignant neoplasms with a clearly documented single site or laterality. Check documentation if the cancer is male breast, because this code is female-specific.
Coding tip
Query for laterality and exact breast site before assigning C50.819 when the note is incomplete.