Giant fibroadenoma mimicking phyllodes tumor: diagnostic pitfalls and surgical management in an adult patient – a case report and review of the literature

Abstract

Giant fibroadenoma is a rare fibroepithelial neoplasm, particularly in adult women. Its rapid expansion creates a diagnostic dilemma, as it often obscures the distinction between phyllodes tumors and malignancies on clinical and radiographic grounds. A 36-year-old woman presented with recent-onset breast asymmetry. Clinical examination revealed a large, firm, mobile mass in the left breast without skin changes or lymphadenopathy. Ultrasonography demonstrated a well-defined hypoechoic mass (117 × 103 × 60 mm), classified as Breast Imaging-Reporting and Data System 4A. Core needle biopsy (CNB) showed benign stromal fibrosis with degenerative changes; however, radiologic–pathologic discordance was noted. Complete surgical excision was performed. Histopathology confirmed a benign giant fibroadenoma. Postoperative recovery was uneventful, with an excellent cosmetic outcome. This case highlights the diagnostic limitations of CNB in large fibroepithelial lesions and underscores the importance of clinicoradiologic–pathologic correlation. Surgical excision provides a definitive diagnosis and favorable cosmetic results.