Recurrent giant fibroadenomas with transformation to cystosarcoma phyllodes in a 17-year-old girl: a rare case report from Syria

BACKGROUND: Fibroadenoma is the most prevalent benign breast lesion that generally affects middle-aged women; it is rare in adolescents and younger children. The transformation into malignancy is not common. However, multiple recurrences of rapidly enlarging fibroadenomas suggest a high possibility of transforming into phyllodes tumors, which are uncommon fibroepithelial lesions that account for 0.3–0.5% of female breast tumors and typically present in premenopausal women. CASE PRESENTATION: We report a case of a 17-year-old Syrian girl who previously had three episodes of recurrence of multiple rapidly enlarging fibroadenomas in her left breast and underwent three operations for complete resection of the lesions. However, a few months later, she was readmitted with multiple large masses in the same breast, and pathological findings confirmed a surprising combination of multiple fibroadenomas for the fourth time with a malignant phyllodes tumor (cystosarcoma phyllodes). The patient underwent lumpectomies followed by adjuvant radiotherapy. Long-term follow-up was recommended. CONCLUSION: Our patient had an extraordinary number of episodes of recurrence at a young age and a rare combination of malignant and benign lesions in the same breast with multiple recurrences. We present her unique, very challenging case with the aim of highlighting the importance of clinical correlation, detailed diagnosis, and careful follow-up.