ICD-10-CM Code for Right-Sided Hormone Receptor-Positive, HER2-Negative Breast Cancer
The ICD-10-CM code for right-sided hormone receptor-positive, HER2-negative breast cancer is C50.911 (malignant neoplasm of unspecified site of right female breast) combined with appropriate laterality and site-specific codes if the exact quadrant or location is known.
Code Structure and Selection
The ICD-10-CM coding for breast cancer requires specifying:
- Laterality (right vs. left breast)
- Anatomic site within the breast (if known)
- Histologic type (if specified)
Primary Code Options for Right Breast
For right-sided breast cancer, the base codes follow the C50.x1x pattern where the "1" indicates right breast:
- C50.011 - Malignant neoplasm of nipple and areola, right female breast
- C50.111 - Malignant neoplasm of central portion of right female breast
- C50.211 - Malignant neoplasm of upper-inner quadrant of right female breast
- C50.311 - Malignant neoplasm of lower-inner quadrant of right female breast
- C50.411 - Malignant neoplasm of upper-outer quadrant of right female breast
- C50.511 - Malignant neoplasm of lower-outer quadrant of right female breast
- C50.611 - Malignant neoplasm of axillary tail of right female breast
- C50.811 - Malignant neoplasm of overlapping sites of right female breast
- C50.911 - Malignant neoplasm of unspecified site of right female breast (use when specific location is not documented)
Important Coding Considerations
The hormone receptor status (HR-positive) and HER2 status (HER2-negative) are NOT captured in the ICD-10-CM diagnosis code itself. These molecular markers are critical for treatment decisions 1, 2, 1 but are documented separately in the medical record and pathology reports, not encoded in the primary diagnosis code.
What the ICD-10 Code Does NOT Include
- Estrogen receptor (ER) status
- Progesterone receptor (PR) status
- HER2 status (negative, low, or positive)
- Grade or stage information
- Histologic subtype details beyond basic morphology
Additional Coding Requirements
To fully document the clinical picture, you should also code:
- Stage - Use appropriate TNM staging codes (if applicable)
- Personal history codes - If this is recurrent disease
- Metastatic sites - If distant metastases are present (C77.x for lymph nodes, C78.x-C79.x for distant sites)
Clinical Context from Guidelines
The distinction between hormone receptor-positive and HER2-negative breast cancer is clinically significant 1. Approximately 80-85% of breast cancers are HER2-negative, and among these, the majority are hormone receptor-positive 1. This subtype is typically treated with endocrine therapy as the backbone of systemic treatment 2, 3, making accurate documentation of receptor status essential even though it's not reflected in the ICD-10 code.
Common Pitfall to Avoid
Do not attempt to create a "custom" ICD-10 code that includes receptor status. The coding system does not support this level of molecular detail. The receptor status must be documented in the clinical notes, pathology reports, and treatment plans, but the ICD-10 code remains anatomically based.