11th April 2024

Proliferative lesions without atypia

An intraductal papilloma is a multitude of papillary cells that grow from the wall of a duct into its lumen. Solitary intraductal papillomas may present with nipple discharge, with bloody discharge being a common presentation. Solitary lesions can be identified on ultrasound, mammography and MRI. After imaging, a CNB can be performed. Solitary papillomas without atypia and with imaging concordance do not require excision, and patients will likely be offered follow-up. Excision may be performed for symptomatic relief. Multiple papillomas (henceforth, diffuse papillomatosis) are defined as five or more papillomas within a localised segment of breast tissue. Definitive management is excision, as the risk of subsequent breast cancer is not well defined. 

Sclerosing adenosis is a benign lobular lesion featuring interspersed glandular cells and increased fibrous tissue. It can present as a suspicious finding on mammography. It is benign in itself but associated with an increased risk of future breast cancer compared to the general population. There is currently no single treatment approach or screening recommendation for sclerosing adenosis without atypia. Complex sclerosing lesions (also known as radial scars) are usually incidental discoveries on biopsy or excision. They are characterised by a fibroelastic core with radiating ducts and lobules. Complex lesions identified on biopsy should be excised. 

Fibroadenomas are the commonest benign breast tumour. They are well-defined, mobile on examination, and appear as solid masses on ultrasound scans. The exact aetiology is not known; however, hormones likely play a role. Definitive diagnosis can only be confirmed with a CNB (or excision). Simple fibroadenomas contain both glandular and fibrous tissue. Excision is not necessary in all cases; asymptomatic biopsy-proven simple fibroadenomas can be ignored. Complex fibroadenomas have histopathological proliferative changes. Examples of these proliferative changes include sclerosing adenosis, duct epithelial hyperplasia and epithelial calcification. There is no consensus on the management of complex fibroadenomas, CNB versus complete excision, and a case-by-case approach is adopted. 

Adenomas are pure epithelial breast tumours. Their sparse stromal elements distinguish them from fibroadenomas. The two main groups are tubular and lactating adenomas.