Granulomatous mastitis, unspecified breast

This code identifies a non-infectious, inflammatory condition of the breast characterized by the formation of granulomas. It typically presents as a firm, often painful, breast mass that can mimic malignancy. The inflammation is not caused by an identifiable pathogen.

Apply this code when documentation specifies granulomatous mastitis without further detail regarding the affected breast. This diagnosis is often confirmed via biopsy showing non-caseating granulomas. Use when the laterality (left or right breast) is not documented or is unknown.

• Do not use this code if the laterality of the affected breast is specified; instead, use N61.21 for right breast or N61.22 for left breast.
• Distinguish from other forms of mastitis (e.g., N61.0 for inflammatory mastitis, N61.1 for chronic mastitis) which have different etiologies.
• Ensure the pathology report or clinical notes explicitly state "granulomatous mastitis" to support this diagnosis.