Secretory Breast Carcinoma in a 5-Year-Old Girl: A Rare Pediatric Breast Malignancy

Secretory breast carcinoma (SBC) is an exceptionally rare malignancy in children, accounting for less than 1% of paediatric cancers and under 0.15% of all breast malignancies. We report a 5-year-old girl who presented with a painless, slow-growing left breast lump for three months. Examination revealed a 6 × 6 cm firm, mobile mass beneath the nipple–areolar complex. Ultrasound showed a cystic lesion suggestive of benign aetiology, and wide local excision was performed. Histopathology revealed secretory breast carcinoma with a triple-negative immunophenotype. A modified radical mastectomy with axillary lymph node dissection was subsequently performed, revealing clear surgical margins and lymph nodes free of metastasis. The patient recovered well and has remained disease-free after six months of follow-up. This case underscores the importance of considering SBC in the differential diagnosis of pediatric breast masses and highlights surgical excision as the mainstay of treatment, with excellent short-term outcomes.