N63.0Unspecified lump in unspecified breast

N63.0 is the ICD-10-CM diagnosis code for unspecified lump in unspecified breast. It belongs to category N63 (unspecified lump in breast), block N60-N65 (disorders of breast) and chapter 14 (diseases of the genitourinary system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within N63, choose N63.0 (unspecified breast) only when documentation doesn't support a more specific option: the right breast (N63.1), the left breast (N63.2), axillary tail (N63.3) and subareolar (N63.4).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 600 (Non-Malignant Breast Disorders with CC/MCC, relative weight 0.9975) and DRG 601 (Non-Malignant Breast Disorders without CC/MCC, relative weight 0.6017), in MDC 09 (Diseases and Disorders of the Skin, Subcutaneous Tissue and Breast), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It was added in FY2018, effective October 1, 2017.

Before ICD-10, this condition was coded in ICD-9-CM as 611.72 (lump or mass in breast).