Giant Juvenile Fibroadenoma Presenting as Rapid Breast Enlargement: A Case Report

Introduction: Giant juvenile fibroadenoma is an uncommon variant of breast fibroadenoma characterized by rapid growth and breast deformity in young patients, with phyllodes tumor being its main differential diagnosis. The relevance of this case lies in its rapid growth, large size, and benign imaging characteristics (BI-RADS 2), which pose diagnostic and therapeutic challenges in clinical decision-making. Case presentation: A 19-year-old female patient presented with progressive enlargement of the left breast over a two-month period, associated with occasional pain. Physical examination revealed a well-defined mass measuring approximately 10 cm. Ultrasound demonstrated a circumscribed solid lesion classified as BI-RADS 2, consistent with a benign lesion. Due to the rapid growth, tumor size, and aesthetic compromise, direct surgical excision without preoperative biopsy was decided upon, considering the low suspicion of malignancy and the clinical impact of the mass. Results: A tumor measuring 10 × 8 cm and weighing 550 g was removed. Histopathological examination confirmed fibroadenoma, with no evidence of phyllodes tumor or malignancy. The postoperative course was favorable, without complications or recurrence at six months of follow-up. Conclusion: Giant juvenile fibroadenoma should be considered in rapidly growing breast masses in young patients. This case highlights that, in clinical and imaging contexts suggestive of benignity, direct surgical treatment without prior biopsy may be an appropriate option. Timely resection allows confirmation of the diagnosis, preservation of breast symmetry, and satisfactory aesthetic outcomes, providing a clinically applicable lesson for decision-making.