ICD-10 Code C50.912: Malignant Neoplasm of Unspecified Site of Left Female Breast
ICD-10-CM code C50.912 is used to report a malignant neoplasm of the left female breast when the exact anatomical site within the breast is not specified in the medical record. This diagnosis code is essential for accurate clinical documentation, cancer reporting, and reimbursement when detailed tumor location information is unavailable.
This guide explains the meaning of C50.912, when to use it, common symptoms, related ICD-10 codes, coding guidelines, common mistakes, and authoritative resources.
Related: ICD-10 Code C50.911: Malignant Neoplasm of Unspecified Site of Right Female Breast
What Is ICD-10 Code C50.912?
C50.912 represents breast cancer of the left female breast with an unspecified site. It should be assigned when:
- A malignant tumor of the left breast is confirmed, and
- The medical documentation does not identify the specific quadrant or location within the breast.
This code belongs to the ICD-10-CM category C50 (Malignant neoplasms of breast) and is a billable diagnosis code used for claims submission and clinical reporting.
Detailed Description of C50.912
ICD-10-CM code C50.912 applies to female patients diagnosed with breast cancer affecting the left breast, when the precise tumor location—such as upper-outer quadrant, central portion, or overlapping sites—is not documented.
The phrase “unspecified site” reflects a lack of documented anatomical detail, not diagnostic uncertainty. Whenever clinical records provide more specificity, coders should assign the most accurate site-specific C50.x code instead of an unspecified option.
Common Symptoms Associated With Left Breast Cancer
Patients with a malignant neoplasm of the left breast may present with symptoms such as:
- A lump or palpable mass in the left breast
- Changes in breast size, shape, or contour
- Skin changes, including dimpling, redness, or thickening
- Nipple discharge (clear or bloody)
- Breast or nipple pain and tenderness
- Partial or complete swelling of the left breast
⚠️ Clinical note: These symptoms are not diagnostic on their own. ICD-10 code C50.912 should only be assigned after confirmation through imaging, biopsy, or pathology.
Related and Similar ICD-10 Codes
Depending on laterality, gender, and documentation specificity, the following codes may be appropriate alternatives:
| ICD-10 Code | Description |
|---|---|
| C50.911 | Malignant neoplasm of unspecified site of right female breast |
| C50.919 | Malignant neoplasm of unspecified site of unspecified female breast |
| C50.922 | Malignant neoplasm of unspecified site of left male breast |
| C50.929 | Malignant neoplasm of unspecified site of unspecified male breast |
👉 Best practice: Always code to the highest level of specificity supported by provider documentation.
ICD-10 Coding Guidelines for C50.912
To ensure compliant and accurate coding, follow these guidelines:
1. Confirm the Diagnosis
- The medical record must clearly document a malignant neoplasm of the left breast.
2. Use Only When the Site Is Unspecified
- Do not use C50.912 if the tumor location within the breast is documented elsewhere in the chart.
3. Gender-Specific Use
- This code is for female patients only.
- Male breast cancer requires different ICD-10 codes.
4. Assign Additional Codes When Applicable
- Use Z17.– codes to identify estrogen receptor (ER), progesterone receptor (PR), or HER2 status when documented.
- Code lymph node involvement or metastatic sites separately when present.
5. Transgender Patient Considerations
- Follow payer-specific, state, or institutional policies when assigning gender-specific diagnosis codes.
Common Coding Errors to Avoid
Avoid these frequent mistakes when assigning ICD-10 code C50.912:
- Using the code without diagnostic confirmation
- Assigning C50.912 when a site-specific breast cancer code is documented
- Using the code for benign breast conditions
- Applying the code to male patients
- Confusing breast cancer with skin malignancies of the breast
Preventing these errors improves claims accuracy and reduces audit risk.
Key Resources for Accurate C50.912 Coding
To stay current with breast cancer coding standards, refer to:
- ICD-10-CM Official Guidelines for Coding and Reporting
- Centers for Medicare & Medicaid Services (CMS)
- American Health Information Management Association (AHIMA)
- American Academy of Professional Coders (AAPC)
- ICD-10-CM codebooks and certified coding software
These resources support compliant coding, accurate reimbursement, and high-quality clinical documentation.
Frequently Asked Questions
What does ICD-10 code C50.912 represent?
It represents a malignant neoplasm of an unspecified site of the left female breast.
When should C50.912 be used?
Use this code when breast cancer is confirmed, but the exact tumor location within the left breast is not documented.
Is ICD-10 code C50.912 billable?
Yes. C50.912 is a billable ICD-10-CM diagnosis code.
Can C50.912 be used for male patients?
No. Male breast cancer requires separate ICD-10 codes.
Should hormone receptor status be coded separately?
Yes. Assign Z17.– codes when estrogen, progesterone, or HER2 receptor status is documented.
Conclusion:
ICD-10-CM code C50.912 is essential for accurately documenting cases of left-sided female breast cancer when the tumor site is unspecified. Proper use ensures:
- Clear and consistent clinical documentation
- Appropriate treatment planning
- Accurate billing and reimbursement
- Reliable cancer data reporting
Whenever possible, coders should assign site-specific breast cancer codes. When detailed documentation is unavailable, C50.912 provides a compliant and standardized solution.
