Cystic neutrophilic granulomatous mastitis: radiologic features and clinical management

Cystic neutrophilic granulomatous mastitis is a rare benign breast inflammatory disease often associated with Corynebacterium kroppenstedtii. Its clinical and radiologic features frequently mimic breast carcinoma, leading to diagnostic and therapeutic dilemmas.

We present a North African 41-year-old woman with pituitary insufficiency who developed a painless, enlarging breast mass. Multimodality imaging (ultrasound, mammography, computed tomography, and magnetic resonance imaging) all suggested malignancy, with magnetic resonance imaging classified as Breast Imaging-Reporting and Data System 5. Core needle biopsy suggested cystic neutrophilic granulomatous mastitis. Due to discordance between suspicious imaging and benign histology, the patient underwent surgical excision. Final pathology confirmed cystic neutrophilic granulomatous mastitis. At 12-month follow-up, the patient remained recurrence free.

This case highlights the diagnostic challenge of cystic neutrophilic granulomatous mastitis, particularly when imaging strongly suggests carcinoma. It emphasizes the indispensable role of histopathology and the need for multidisciplinary management to avoid overtreatment.