Leiomyoma of the breast
A leiomyoma is a benign tumor of smooth muscle cells. Indeed, let’s have a little latin, so, ‘leio‘ means ‘smooth’ ‘myo‘ means ‘muscle’ and ‘oma‘ means ‘tumor’. So, the description is in the name really.
However, please don’t worry because this is a benign lesion. Furthermore, this lesion can occur in various places around the body, and very rarely occurs in the breast.
Leiomyomas most commonly occur as uterine fibroids and sometimes they occur in the muscles and occasionally in the gut.
Specialists often group this type of tumor under an informal category of ‘stromal’ tumors; for example, solitary fibrous tumors and myofibrobastomas. These tumors develop from immature muscle and connective tissue cells. In addition, these tumors can vary subtly on presentation.
The composition of a leiomyoma is mainly ‘mature’ (well differentiated) smooth muscle cells.
It is important to note that these neoplasms do not develop from either glandular or epithelial cells. Such growths are a common source of many benign fibrocystic breast changes, but also breast cancer development.
Typically, a breast leiomyoma will either develop from smooth muscle cells in the breast duct lining, or from smooth muscle elements of blood vessels. Happily, these tumors are neither malignant nor premalignant, and are more of an inconvenience than anything else.
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Slightly more Common in Women than Men
Breast leiomyomas are slightly more common in females than males overall. Further, these harmless tumors tend to develop later in life, often between 55 and 70 years of age.
These types of tumors tend to occur in the subareolar region (below the nipple), and for no known reason, they tend to occur most often in the right breast.
Breast Vascular leiomyoma (angioleiomyoma) and ‘cutaneous’ Leiomyomas
When this neoplasm forms from smooth muscle tissue in the lining of blood vessels, the tumor is often referred to as a ‘vascular’ leiomyoma.
Howevever, the formation of a leiomyoma within the dermis in any region of the body, is a ‘cutaneous’ leiomyomas.
These cutaneous (‘relating to the skin’) tumors tend to be very small, and often occur in groups or multiples, and are more likely to be superficial and palpable.
Pathological features of breast leiomyoma
Leiomyomas which are visible or palpable may take on a yellow or yellowish-pink appearance. They also tend to be rather firm to the touch.
The histological features of breast leiomyomas tend to be almost identical to leiomyomas occurring at other sites.
So these tumors tend to display bundles of ‘spindle-like’ cells with ‘blunt’ nuclei. The cytoplasm is highly eosinophilic (stains readily for protein-sensing dyes), and stain positive for vementin, desmin, and especially smooth-muscle-specific actin.
On mammogram, this tumor will tend to show a sharply defined border and will lack the irregular and random appearances typical of breast carcinoma. However, breast cancer can not be ruled out by mammogram alone.
Breast leiomyomas usually appear homogeneous and moderately to highly dense. They are also ‘negative’ for certain features that might suggest ductal carcinoma.
Such features suggestive of ductal carcinoma include:-
- Architectural distortion
- Skin thickening
- Nipple retraction.
Breast Leiomyomas on Ultrasound
On ultrasound these breast tumors are mainly solid, homogeneous and well circumscribed nodules, without apparent cystic features (fluids).
Leiomyomas also tend to very closely resemble fibroadenoma (also benign) on sonography and mammography, so a microscopic and histological evaluation is necessary.
Once the pathologist analyzes the biopsy sample, it is fairly easy to determine that a leiomyoma is not breast cancer. However, in terms of differential diagnosis, the most likely point of confusion surrounding a leiomyoma are the similarities to leiomyosarcoma of the breast (muscle cancer), which is prone to metastasis.
Treatment and management of breast leiomyoma
Leiomyomas can cause pain and swelling in the nipple-areola complex of the breast. So, treatment basically revolves around the management of symptoms.
If the tumor is not causing any problems, it might be left alone. Otherwise, treatment may involve a surgical excision. There is also some evidence to suggest that tamoxifen therapy (a chemical often used to treat various cancers) can cause these breast tumors to grow quickly and enlarge.
Here are the most popular Q&A’s about this topic…
Where can leiomyoma be found?
In the heart and uterus. A leiomyoma of the uterus is commonly called a fibroid.
What causes leiomyoma?
- Genetic changes
- Other growth factors
How common are leiomyoma?
As many as 3 out of 4 women have this at some point during their lives, but most are unaware of them because they often have no symptoms.
How to diagnose leiomyoma?
Ultrasound and lab tests if you have symptoms. If a traditional ultrasound does not provide enough information, your doctor may suggest MRI, hysterosonography, hysterosalpingography, myomectomy, or hysteroscopy.
What are the Symptoms of a Leiomyoma?
- Heavy menstrual bleeding
- Prolonged periods (7 days or more)
- Pelvic pressure or pain
- Frequent urination
- Difficulty emptying the bladder
- Pain on intercourse
- Backache or leg pains.
What are the leiomyoma risk factors?
There are a few known risk factors for these tumors and these include:-
- Menstruation at an early age
- A diet high in red meat and low in green vegetables and fruit
What are some Complications of Leiomyoma?
Although there are no dangerous complications, these tumors can cause discomfort and may lead to anemia and heavy blood loss.
These tumors do not usually interfere with conception and pregnancy. However, it is possible that leiomyomas can cause infertility or pregnancy loss or prevention of implantation and growth of an embryo.
Also, these tumors can also block fallopian tubes or interfere with the passage of sperm from the cervix to the fallopian tubes.
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