Consultant Oncoplastic Breast Surgeon
Aberdeen Royal Infirmary, Scotland
Yazan Masannat, Consultant Oncoplastic Breast Surgeon, Aberdeen Royal Infirmary
Fibroadenomas are one of the most common forms of benign breast disease. Whilst they may occur at any age, they are most common in premenopausal women. In the majority of cases they present as a solitary breast lump, which is well circumscribed and mobile. Modern diagnostic techniques have superseded the need for excision biopsy of suspected fibroadenomas however some patients require surgery..
The prevalence of fibroadenomas is difficult to quantify but has been estimated between 7% and 13%. The most common age for development is in the second and third decades of life. Risk factors for the development of fibroadenoma include higher socioeconomic class and the presence of dark skin.
The commonest presentation is to the symptomatic breast clinic with a breast lump in the younger age group while in the older population they may be found incidentally on screening. They present as a solitary, smooth, rubbery mobile breast lump which is non tender. Normally the range of diameter is 1-3cm, if a fibroadenoma grows to greater than 5cm this is referred to as giant fibroadenoma.
Fibroadenomas are part of ANDI (Aberration of Normal Development and Involution). It usually arises from the terminal ductal-lobular Unit and is composed of epithelial and connective tissue components. They are influenced by hormonal variation.
Between the ages of 15 and 25, under the influence of cyclic exposure to sex hormones, the breast develops lobules in addition to the ducts which develop during puberty. Commonly hyperplastic lobules develop at this stage in development. Fibroadenoma occur in a single breast lobule, histologically they are identical to hyperplastic lobules. They contain both epithelial and stromal cells. Like normal breast lobules fibroadenoma are responsive to hormones, demonstrating growth when exposed to sex hormones and involution following menopause.
Approximately 4% of all fibroadenomas are greater than 5cm, referred to as giant fibroadenomas. They develop in the adult breast, during pregnancy or lactation in most cases. They are referred to as juvenile giant fibroadenomas when developing in the adolescent.
An estimated 1 in 10 patients with a single fibroadenoma will have further present in their breasts. Unlike in solitary lesions, there is some evidence to suggest that there may be a familiar component to the development of multiple fibroadenoma.
The appearance of a fibroadenoma on ultrasound is a smoothly contoured lesion with weak internal echoes and uniform distribution. Mammography may be useful in the diagnosis of fibroadenoma in older patients. Classically the appearance of fibroadenoma on mammography is of a mass well demarcated from the surrounding tissues exhibiting a surrounding area of radiolucency known as the halo sign. Fibroadenomas may also contain areas of calcification.
Fine needle aspirate (FNA) of fibroadenoma may demonstrate benign epithelial cells and myoepithelial cells both of which are normally contained within breast parenchyma. The addition of fine needle aspirate to ultrasound in the investigation of fibroadenoma significantly increases both the diagnostic accuracy and the accuracy in exclusion of malignancy.
The development of a fibroadenoma is thought to occur over a 12 month period. More than half will stay the same size after diagnosis, about a third will decrease in size and less that 10% will increase in size. Excision is recommended for the ones that are increasing in size, or if on diagnosis they are more than 4cm, or if the diagnosis is in doubt on triple assessment.
The following video shows excision of a recurrent fibroadenoma
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