A 5-year case review of granulomatous mastitis

Introduction

Granulomatous mastitis is a rare inflammatory condition said to predominate in women of reproductive age, often presenting as a lump that may mimic malignancy.

Methods

The histopathology database was searched for 'granuloma-tous mastitis' over 5 years. Case notes, imaging, and pathology were reviewed.

Results

Seven cases were identified. The age range was 34 to 72 years, and mean age was 54 years. Presentation was a lump in two cases, chronic breast infection in three, indeterminate mass on screening mammogram in one, and a suspicious mass and large axillary node on screening mammogram in one. Two cases had imaging features suggesting malignancy; one was a lump at the site of previous breast cancer excision and the other was a screen-detected mass in a patient with a chronic skin condition. Fine needle aspiration cytology was C2 in six cases and C1 in one case. Five of the C2 results gave a diagnosis of granulomatous mastitis, the sixth was abscess. Core biopsy was carried out in three cases: a suspicious screening case with C2; for exclusion of malignancy in a probable abscess; and multiple suspicious masses with C1 cytology. In all three cases core biopsy showed B2 granulomatous mastitis. Only one case went for operation: multifocal suspicious masses in a patient with previous ipsilateral breast cancer, with histopathology confirming granulomatous mastitis.

Conclusion

This series confirms that granulomatous mastitis is uncommon. Only two patients were premenopausal. In three patients there was clinically apparent chronic inflammation. In only two cases was malignancy considered the most likely diagnosis.