Fibroadenoma of Breast

Fibroadenomas are benign tumors composed of stromal and epithelial elements. The stroma varies from myxoid and hypocellular to fibrous and moderately cellular. Involution is common with increasing age of the lesion. The stroma becomes less cellular, more fibrotic and hyalinized. Hence, fibroadenoma with mixoid features should be seen normally in young age women. The cause of these tumors is unknown. Approximately 10% of fibroadenomas disappear spontaneously each year, and most stop growing after they reach 2-3 cm. In 72% of cases, they spontaneously resolve over a period of 7 years.
In most cases, fibroadenoma is considered to be abberation of normal breast development.
However, it is an abnormal variant of mixoid fibroadenoma, when it is associated with Carney's Syndrome, a rare inherited (autosomal dominant) abnormality that involve the following conditions: (1) adrenal gland, a small gland located above each kidney, over produces cortisol hormone with various manifestation such as skin easily bruises, obesity, and menstrual irregularities; (2) multiple pigmented lesions/spots of the skin (e.g. face, eyelid) or mucosa (e.g. conjunctiva, mouth); and (3) a variety of tumors (i.e. mixoid features of benign breast tumour/fibroadenoma is one of them).