What is the ICD‑10‑CM code for malignant neoplasm of the upper‑outer quadrant of the left breast in a female?

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ICD-10-CM Code: C50.412

The ICD-10-CM code for malignant neoplasm of the upper outer quadrant of the left breast in a female is C50.412.

Code Breakdown

The ICD-10-CM coding system uses a hierarchical structure for breast malignancies:

  • C50 = Malignant neoplasm of breast
  • C50.4 = Upper-outer quadrant of breast
  • C50.41 = Upper-outer quadrant of breast, specifying laterality
  • C50.412 = Upper-outer quadrant of left breast, female

Important Coding Considerations

Laterality Specification

The sixth character in the code specifies laterality, which is mandatory for accurate breast cancer coding 1, 2, 1:

  • "1" = right breast
  • "2" = left breast
  • "9" = unspecified side (should be avoided when laterality is known)

Sex Specification

The seventh character distinguishes between female and male breast cancer. For female patients, the code ends in "2" as shown above.

Clinical Documentation Requirements

Proper ICD-10-CM coding requires complete pathology documentation including 1, 2:

  • Anatomic site specification with laterality (right or left breast)
  • Quadrant location (upper-outer, upper-inner, lower-outer, lower-inner, or central)
  • Histologic confirmation of malignancy

Common Pitfall

The upper outer quadrant is the most common site for breast cancer to arise 3, making accurate quadrant documentation particularly important. Ensure the clinical documentation explicitly states "upper outer quadrant" rather than general descriptors, as this affects code selection and subsequent data analysis for treatment planning and outcomes research 4, 5.

References

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