Fibroadenoma of the breast in an 11-year-old girl.

Fibroadenoma is the main cause of unilateral breast mass in teenagers and adolescents. 4% of these are a special form described as giant or juvenile fibroadenoma. For primary diagnosis, ultrasound is the method of choice. The MRI allows exact evaluation of size and location. The fibroadenoma must be distinguished from the phylloid tumour, which can be malignant. The latter occurs in patients of all ages, but peaks between the ages 40 and 50 years. Only 2% of all primary malignant breast lesions are found in women aged under 25. Metastases of other primary tumours must be excluded, especially with a history of prior malignancies. When planning the surgical excision, the final cosmetic result is important. Although the main reason of an asymmetrical breast enlargement of young girls is a benign mass, an early surgical excision is efficient with regard to the best possible cosmetic outcome.