Difference Between Sclerosing Adenosis and Fibroadenoma

Sclerosing adenosis is a histological feature encountered as lumps with clear margins in the breast accompanied by scar-like tissue. Interestingly, sclerosing adenosis can be a feature of fibroadenomas, making them complex fibroadenomas. Fibroadenoma is an epithelial lesion that present a firm, smooth and well-defined growth that can often be moved around under the skin.

What is sclerosing adenosis?

Definition:

It is a benign breast disease with more than the normal number of milk-producing glands that are enlarged and distorted. This condition affects the epithelial and mesenchymal tissues of the breast. Adenosis is often encountered in women with breast fibrosis or cysts. It is the presence of fibrous scar-like tissue (stromal fibrosis) that is the hallmark of sclerosing adenosis.

Causes and risk factors:

Sclerosing adenosis has been correlated with increased breast cancer risk. In the presence of sclerosing adenosis, the standardized incidence ratios for breast cancer are elevated (2.1) while in its absence they are not (1.52). The exact role of sclerosing adenosis in malignancy is poorly understood.

Diagnosis:

Sclerosing adenosis can be properly diagnosed through immunohistochemistry. The affected epithelial and mesenchymal tissues appear in whorls and, as a result, interferes with the glandular structures. At the molecular level sclerosing adenosis is a product of mesenchymal, myoepithelial and epithelial cells.

Symptoms:

Sclerosing adenosis is a complicated infiltration, alteration, and enlargement of lobules with duplicated and crowded acini and stromal fibrosis. The cellular composition is often difficult to discern because of the histological disfigurement, what is discernable is the over-abundance of myoepithelial in addition to luminal epithelial cells. Sclerosing adenosis may can cause discomfort and pain.

Complications:

When sclerosing adenosis is linked to breast cancer the malignant cells can arise directly from the sclerosing adenosis, or close to it and invade the sclerosing adenosis.

Treatment:

Sclerosing adenosis is often left alone but monitored. In cases where removal is necessary, a minor aspirating biopsy can be used to remove the complex sclerosis adenosis.

What is fibroadenoma?

Definition:

Fibroadenoma is among fibroepithelial lesions of the breast in a unique group of neoplasms. They are benign tumors arising from glandular epithelia with fibrous elements. These are the most commonly occurring benign breast tumors, accounting for approximately a third of all benign breast lesions mostly in young women.

Causes and risk factors:

The occurrence of fibroadenomas appears to be linked to reproductive hormones, however, the exact cause is unknown. They often occur during the reproductive years, enlarge during pregnancy and hormone therapy use, and can shrink when hormones levels decrease in menopause.

Complex fibroadenomas have elevated breast cancer risk of around 2.3 to 3.1 compared to the breast cancer risk factor in women with simple fibroadenoma which is approximately 1.5%.

Diagnosis:

Following a physical breast exam, fibroadenomas can be better examined during imaging like a mammogram or ultrasound.

Fibroadenomas are benign stromal tumors that result from monoclonal mesenchymal cells in the stroma and sensitive intralobular polyclonal hyperplasia of intralobular epithelia ducts and acini. The resulting presentation is a compression of acini and ducts into strip-like spaces.

Simple fibroadenomas appear consistent throughout while complex ones have other histological features such as cysts and sclerosing adenosis.

Symptoms:

During a physical breast exam, only large fibroadenomas can be felt. These can feel like a hard and round with distinct margins and can be moved around under the surface. For better diagnosis of the fibroadenoma, a biopsy is needed to know if the growth is cancerous or not.

Complications:

Most fibroadenomas are benign, do not proceed beyond this point and do not affect the risk of breast cancer. However, in complex fibroadenomas, which have other histological features such as cysts or sclerosing adenosis, the risk of breast cancer may increase.

Treatment:

If the lump of the fibroadenoma is small and stays small, it is usually harmless and can be left as is. If the lump changes, grows or becomes painful doctors may recommend removing the growth. Women with fibroadenomas are encouraging to regularly examine their breasts or go for imaging tests to ensure that the fibroadenomas do not become malignant.

Possible similarities

Neither condition is fatal but can be associated with some elevation in breast cancer risk.

Difference between sclerosing adenosis and fibroadenoma: Chart 

Summary

Sclerosing adenosis affects the milk-producing glands by causing enlarged and distorted lobules while fibroadenoma is among fibroepithelial lesions that arise from epithelia of the glands and involve some glandular elements. Complex fibroadenoma have additional features including sclerosing adenomas and cysts. Women with sclerosing adenosis alone and complex fibroadenomas both have a higher risk factor for breast cancer than women without either. The risk factor is higher in sclerosing adenosis than in fibroadenomas. The cause of fibroadenomas is unknown but is suspected to be linked to reproductive hormones while sclerosing adenoma appear to form as part of the natural aging process. These conditions are both often benign with no direct link to death.

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