Abstract
Giant phyllodes tumors (PT) are an uncommon fibroepithelial neoplasm and especially rare in adolescent girls. Diagnosis is difficult not only due to the rarity of PT, but also owing to the resemblance of its clinical and imaging features with fibroadenoma. The author reports a case of a giant PT in a 14-year-old girl. Clinical examination showed a large painful mass in the left breast, and an abscess was initially suspected. But magnetic resonance imaging (MRI) displayed features characteristic of PT. Following complete surgical excision of the mass, histopathology confirmed the diagnosis of a benign PT with diffuse myxoid changes, consistent with the MRI findings. This case emphasizes the importance of breast MRI, both for its ability to aid diagnosis, as well as its benefits in guiding the surgical plan.