Breast Cancer - Moose and Doc

A breast cancer explanations website

 

By Dr. Halls

Sebaceous Carcinoma of the Breast

Sebaceous breast cancer is essentially a skin cancer. In this case, the cancer is growing on the skin of the breast. Sebaceous breast carcinoma is not usually related to the conventional ductal carcinomas characteristic of breast cancer.

So, sebaceous cancer is a distinctive type of breast cancer that is characterized by unequivocal morphologic differentiation towards sebaceous epithelium or sebocytes. (Sebocytes are epithelial cells that originate from a basal cell layer at the periphery of the gland).

However, it is also possible for women to have an invasive ductal carcinoma that has many features, or a certain percentage of the tumor, that has commonalities with sebaceous gland carcinomas of the skin. Sebaceous breast cancer is VERY rare.
 

I just want to let you know that I have created a newer version of this page with more up-to-date information on rare types of breast cancer. However, this page still has great material, and I would still recommend on using it as well.

The breast cancer cells resemble skin sebaceous glands

These types of cancers will often contain many lobules and nests of clear cells that closely resemble the sebaceous glands of the skin.

sebaceous carcinoma cells

This type of breast cancer tends to be of a low grade

This type of breast cancer can also sometimes develop within an intraductal breast papilloma.

Specialists tend to consider sebaceous breast carcinomas to be a ‘low grade‘ tumor.  Indeed, they actually most commonly develop in and around the eyelids.

If a sebaceous cancer of the breast show multicentricity, poor differentiation and infiltrative growth, then the tumor may have a worse prognosis. Most patients who develop sebaceous carcinoma of the breast do so in their 60’s or 70’s, though it can sometimes develop a little earlier.

Clinical Presentation of Sebaceous Breast Cancer

A sebaceous carcinoma of the breast will usually present as a small mass.  However, there is always a risk that doctors will dismiss the lesion as something benign, like a common skin lesion.

This is because sebaceous breast cancers are not always easy to see on a screening mammogram either. The size of a sebaceous breast tumor will often range from 1 cm to 4 cm on initial diagnosis.

sebaceous carcinoma-xray

A mammogram will usually reveal pleomorphic calcifications, and these lesions are often well circumscribed.

Histological Features

Well-defined solid sheets or lobules of atypical epithelial cells usually define sebaceous carcinoma of the breast.  These cells also frequently include many large pale or clear cells, often with ‘scalloped’ nuclei.

The cytoplasm is usually coarsely vacuolated, and abundant lipid droplets can often be identified in the cytoplasm with oil-red-O staining.

Important differentiation from squamous and basal cell breast carcinomas

The clear cells of sebaceous carcinoma of the breast tend to be negative with alcian blue and periodic acid-Schiff and staining.

The atypical epithelial tumor cells tend to test positive for the epithelial membrane antigen, human milk fat globules subclass 1, human milk fat globules subclass 2 and Leu M1.

Breast sebaceous tumor cells tend not to express:-

sebaceous carcinoma cells2

Sebaceous breast carcinomas are also frequently reactive for Cam 5.2, and  BRST-1. This can be an important means of differentiating sebaceous gland breast carcinomas from squamous cell breast carcinomas and breast basal cell carcinomas.
 
Sebaceous carcinoma of the breast is quite often positive for cytokeratin, but not for vimentin and carcinoembryonic antigen. Most of the tumor cell nuclei in sebaceous breast carcinoma will be reactive for antibodies to progesterone and estrogen receptors, but not for the HER2/neu protein.

Outlook and treatment for breast sebaceous carcinoma

Medics and specialists do not know a great deal about sebaceous carcinomas of the breast because it is so very rare.

However, if we take the example of a skin sebaceous carcinoma, then clearly, sebaceous breast carcinoma should be considered aggressive cancer.

Sebaceous cell breast tumors will likely exhibit an aggressive clinical course, with a significant tendency for both local recurrence and distant metastasis.

Surgery followed by chemotherapy is common

Surgeons will normally completely excise a sebaceous carcinoma of the breast. A modified mastectomy is sometimes necessary, and depending on the situation an axillary lymph node dissection might be prudent.

Follow-up should be frequent in order to look for possible metastasis.  Physicians will commonly treat sebaceous carcinoma of the breast with chemical agents such as interferon with retinoids.

Another useful treatment for sebaceous carcinoma of the breast is radiation therapy .  However, without the full surgical removal of the carcinoma, these attempts tend not to be that successful.

The main concern with sebaceous breast cancer is a delay in diagnosis

The main factor affecting the outcome of sebaceous cell cancer of the breast will likely be an unfortunate delay in proper diagnosis and treatment.

Sometimes doctors initially dismiss the lesion as a mild skin disease.  However,  if there is any doubt it is very important to obtain a biopsy.

Studies estimate that the rate of local recurrence for breast sebaceous carcinoma can be as high as the 30% range.  Furthermore, local recurrence is likely to happen within the first five years following treatment.

If there is no regional metastasis and no local or regional progression of the disease, then the outlook for breast sebaceous carcinoma is good.

If a patient with sebaceous breast carcinoma has experienced metastatic disease, then the chances of surviving beyond five years are unfortunately probably in the 50% range only.

Further Reading

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References

More references for this section are on this page.

About Steven Halls

Dr Halls has 25 years experience as a radiologist. He worked for 13 years at Cross Cancer Institute in Edmonton, a world-class cancer treatment facility. He has had high-volume experience with cancer, interventional procedures, clinical trials and his own phase 1 and 2 research in MRI and breast cancer staging.