Background: Fibroadenomas are benign breast tumours that are commonly diagnosed in young women in their 20's and early 30's. Occurrence of malignancy in the breasts of these women is very rare.
Method and result: We report a case of an infiltrating ductal carcinoma within an otherwise benign fibroadenoma in a 23-year-old woman. She presented with a lump, approximately 7cm in diameter, in her right breast. There were no palpable axillary and supra- clavicular lymph nodes. Excision biopsy was carried out and histopathological report showed it to be a fibroadenoma coexisting with infiltrating ductal carcinoma.
Conclusion: Fibroadenomas are commonly diagnosed in patients in their 20's when the risk of developing breast cancer is extremely rare. Despite this rarity all excised breast lumps should be subjected to histopathological evaluation in order to avoid a diagnostic pitfall.