ICD-10 Code C50.81 – Malignant neoplasm of overlapping sites of breast, female (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C50.81 – Malignant neoplasm of overlapping sites of breast, female
What it is
This code identifies a malignant breast tumor in a female when the cancer spans overlapping sites of the breast and cannot be assigned to one specific quadrant or region. Use it when the record clearly documents overlapping involvement.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include a breast mass, skin or nipple changes, pain, or abnormal imaging results, but the code is based on the documented anatomic site, not the symptoms alone.
When to use this code
Use C50.81 when the provider documents primary breast cancer in a female and specifies overlapping sites of the breast. This is appropriate when the tumor crosses boundaries of more than one breast region and a more specific site is not stated. Check documentation for laterality and whether the neoplasm is primary, secondary, or in situ.
Do not use for
Do not use this code for benign breast tumors, unspecified breast malignancy, or non-overlapping site-specific breast cancers. If the record does not clearly support overlapping sites, check documentation.
Coding tip
Capture the exact site wording from the pathology or oncology note, and verify whether laterality or more specific breast location coding is required.