Transformation of a Breast Fibroadenoma to Borderline Phyllodes Tumor in a 20-Year-Old-Girl with Diagnostic Difficulties: A Case Report & Review of Literature

We are reporting a rare case of 20 year old girl who presented with lump in the left breast at the age of 18 years. She underwent Fine Needle Aspiration Cytology (FNAC) twice and it was diagnosed as fibroadenoma. Conservative treatment had been advised to her but within next two years, there was gradual increase in the size of the lump to acquire a size of 4x3 cm. Again she underwent evaluation outside with repeat FNAC which was reported as benign breast disease. After consultation with us, we had advised core needle biopsy which was indeterminate. Therefore, we planned wide local excision of the lesion and final pathology turned out as borderline phyllodes tumor. Phyllodes tumor are not true sarcomas. Sometimes they have cystic components also. Their biological behavior and cellular origin is different from the origin of true sarcomas. Most commonly they occur in females with median age of presentation of 42 to 45 years. High grade tumors are found in elderly patients. Clinically approximately 20 % of these tumors presents as non palpable lesion which is picked up by screening mammography.

Conclusion: The definitive histopathological diagnosis of phyllodes tumor is possible only after surgical excision and the principle of surgical excision is excision with clear wide margins to avoid local recurrence.