What is Breast Myofibroblastoma?
Myofibroblastoma is a unique, non-cancerous breast tumor that is more commonly found in men. This type of tumor was first identified in 1987, and since then, there has been a variety of studies examining it from surgical, radiographical, and pathological perspectives. Because it is so rare, it can be challenging for pathologists to tell it apart from other benign and malignant tumors when they examine a biopsy, which is why they often have to remove it for closer inspection.
When felt, the myofibroblastoma presents as a solid, movable lump. On a microscopic level, the tumor has a clear border and is composed of cluster of irregularly arranged, elongated cells mixed with fat cells, all set within a backdrop of a collagenous and fluid-like matrix. Doctors can use tools like ultrasound and mammograms to diagnose the tumor, although it can sometimes be mistaken for other types of lumps because of how it looks on the imaging scans.
Myofibroblastoma is frequently mixed up with another benign condition called spindle cell lipoma as well other cancerous and non-cancerous breast conditions. The typical way to manage it is through surgery to remove the tumor. As far as we know, myofibroblastoma does not have the potential to turn cancerous or come back after removal.
What Causes Breast Myofibroblastoma?
Myofibroblastoma of the breast is a rare non-cancerous tumor that was first discovered and documented in 1987. Its first case was noted in 1981. While it is often found in men, women can also develop it.
This condition usually shows up in people between the ages of 40 and 87, especially among women undergoing menopause and older men. Currently, there’s no evidence that a person’s race, gender, health history, medicines, or hormone supplements have any impact on the likelihood of developing myofibroblastoma.
Risk Factors and Frequency for Breast Myofibroblastoma
Information about myofibroblastoma of the breast is not often published. From the available reports, it is known that this condition has been diagnosed in patients who previously had cancers such as kidney and prostate. Furthermore, in men, it has been linked with gynecomastia, an enlargement or swelling of breast tissue.
Signs and Symptoms of Breast Myofibroblastoma
Myofibroblastoma is a medical condition that typically presents as a single, painless lump, that can be felt and moved under the skin. It grows slowly over several months or even years. The steps involved in diagnosing myofibroblastoma usually involves three key elements: clinical evaluation, imaging tests, and a core needle biopsy.
In the clinical evaluation, doctors ask for a detailed medical history, which may include questions about changes in physical symptoms such as pain cycles, recent injuries, changes in nipple or skin, or nipple discharge. It is also important to know about the patient’s past medical and surgical records, any previous instances of cancer, the family’s history of cancer, lifestyle habits, and current medications.
In women, information about their reproductive and menstrual history – including when their periods started (menarche), if they’ve gone through menopause, or any past use of oral contraceptives or hormone replacement therapies – is also relevant. For men test, doctors might want information regarding the usage of androgen deprivation therapies, especially if the patient has been treated for prostate cancer in the past.
Testing for Breast Myofibroblastoma
When it comes to spotting myofibroblastoma (a kind of tumor), imaging methods don’t always show a definitive picture. However, most cases of this condition in the breast have been identified either through mammograms in women or chest CT scans in men. On a mammogram, they often appear as clear, round or oval shapes that stand out because they are denser than the surrounding breast tissue. Sometimes, there might be areas of coarse calcification (where calcium has built up) inside the tumor.
When it comes to men, it can be tricky to tell the difference between myofibroblastoma and breast cancer because they can look very similar. Gynecomastia, which is breast enlargement in men, might also show up alongside myofibroblastoma, but this isn’t always the case. The tumor can also look similar to a fibroadenoma on an ultrasound scan, appearing as a solid lump that’s more echo-dense (it reflects more soundwaves) than the surrounding tissue. However, sometimes, it may appear as an oval or irregular shape with different patterns of echogenicity, which could be because of the presence of fat and other kinds of tissue inside the tumor. By using a Doppler ultrasound, which shows blood flow, doctors might also be able to see increased blood supply to the tumor from vessels at its periphery.
Magnetic Resonance Imaging (MRI), while not commonly used, can show myofibroblastoma as a mass that lights up more with intravenous contrast, indicating it has a good blood supply. The mass may have internal structures (septations) and display a bright signal on T2-weighted images, suggesting it has a high water content. It might also exhibit abnormal diffusion restriction (limited movement of water molecules) and surround itself with a less intense capsule. The pattern of uptake and washout of contrast on dynamic MRI (plateau kinetics) also aids in its detection. Scientists have discovered that a measurement called the apparent diffusion coefficient (ADC) could be a useful finding for distinguishing myofibroblastoma from other malignant lesions on an MRI. Unlike most tumors, this ADC value is likely to be high.
Diagnosing myofibroblastoma often requires a tissue sample. Doctors may use a small needle to take out some cells (fine-needle aspiration) or remove a chunk of tissue (core needle biopsy). The sample may show non-specific whirls of elongated cells with benign round or oval centers. However, due to the potential lack of cellular material in a sample, fine needle aspiration could lead to non-diagnostic results. Hence, most cases are diagnosed using tissue obtained from a core-needle biopsy.
Treatment Options for Breast Myofibroblastoma
Myofibroblastoma, a non-cancerous condition, can be treated with a minor surgical procedure known as local excision, mainly to alleviate any discomfort or symptoms the patient is experiencing. It’s worth noting that since it’s a benign condition, this surgery isn’t always necessary. However, due to the lack of long-term data on the implications of an untreated myofibroblastoma, most known cases have undergone surgical removal.
This surgical removal, or excision, is regarded as a cure, and it’s rare that the myofibroblastoma would return after the procedure. That said, it’s essential for patients to continue to have check-ups for at least two years following the operation. As of now, there haven’t been any documented cases of a myofibroblastoma turning malignant, or cancerous.
What else can Breast Myofibroblastoma be?
Here’s a look at some conditions and how they appear under a microscope:
Leiomyoma: Under the microscope, you can see cells organized in crisscross patterns with abundant cytoplasm, which is a substance within a living cell, and a little bit of connective tissue in between. Special tests can confirm that these cells respond to estrogen and progesterone, the two main female hormones. The absence of CD34, a cell surface protein, and genetic changes involving HMGA2-RAD51B and FH can also identify this condition.
Solitary Fibrous Tumor: Here, spindle-shaped to oval cells huddle around staghorn-like vessels. The tissue around the vessels may become hardened, and the connective tissue can vary in fiber content. There’s also a variant that contains mature fat cells. Some tests that turn positive for CD34, STAT6, EMA, SMA, and nuclear Rb, but do not react with desmin, can help in diagnosis. The presence of the NAB2-STAT6 fusion can be confirmed with molecular tests.
Spindle Cell Lipoma: It’s characterized by mature fat cells, innocuous-looking spindle cells, thin ‘rope-like’ collagen, and certain types of connective tissue cells called mast cells. The tissue can appear slimy (myxoid) and might not contain a lot of fat. CD34 tests will turn positive but other tests for SMA, desmin, and Nuclear Rb will turn negative.
Fibromatosis: It’s marked by a large amount of collagen, a major component of connective tissue, and can be highly invasive. This condition is often associated with Familial Adenomatous Polyposis (FAP). Tests can reveal positive results for nuclear beta-catenin and Nuclear Rb, but negative for hormone receptors and CD34. Mutations in APC or CTNNB1 genes are common.
Pseudoangiomatous Stromal Hyperplasia (PASH): A common condition in premenopausal women or those on hormone replacement therapy, PASH presents with prominent clefts and fewer cells than in myofibroblastomas. It rarely forms a mass but does encase ducts and lobules. Tests can show it reacts with desmin, SMA, vimentin, estrogen and progesterone receptors, and nuclear Rb.
Nodular Fasciitis: This condition is associated with a prior history of breast injury. Under a microscope, cells in this condition appear fibrous with differing levels of crowding in a tissue culture pattern. There is a mix of tissue types and immune cells found along with some giant cells. Tests can show a negative result for CD34 but positive for SMA, desmin, and nuclear Rb. The presence of USP6 rearrangement can be confirmed molecularly.
Metaplastic Spindle Cell Carcinoma: Here, epithelial cells or cells looking like epithelial cells are found. There are often many abnormal cells dividing and invading normal breast ducts, typically with connective tissue cells. Tests can confirm the positive presence of proteins found in specific types of cells, but a negative reaction to estrogen and progesterone receptors, as well as desmin. Genetic changes involving PTEN, TP53, and EGFR are not unusual.
Invasive Lobular Carcinoma: The cells here are arranged in a particular way, with spaces within their cytoplasm. They’re also known for their infiltrating borders. Atypical Lobular hyperplasia and Lobular carcinoma, both conditions that affect the lobules of the breast, can be present. Cell tests can confirm reactions for estrogen, progesterone receptors, E-cadherin, cytokeratins, and GCDFP-15. Specific mutations in the CDH1 gene have been reported.
Other conditions to rule out include: Benign fibrous histiocytoma, Hamartoma, Fibroadenoma, Low-grade sarcoma, Lymphoma, Malignant fibrous histiocytoma, Phyllodes tumor, Low-grade myofibroblastic sarcoma, and Angiomyolipoma.
What to expect with Breast Myofibroblastoma
The outlook for myofibroblastoma, after being surgically removed, is generally very good. There aren’t any known cases of this condition returning in the same area or turning into a cancerous tumor after surgery.
Possible Complications When Diagnosed with Breast Myofibroblastoma
No long-term problems have been reported in medical studies, other than those typically associated with the type of surgery. This includes both surgeries that try to save as much of the breast as possible and those that remove the entire breast.
Preventing Breast Myofibroblastoma
If a patient’s doctor suspects a breast issue, they will typically send them to a specialist. This could include a breast radiologist and a breast surgeon. These experts can confirm the diagnosis and discuss any treatment options if required.
To diagnose a breast lump accurately, a three-step assessment is necessary. This involves an initial examination by a health professional, followed by imaging (like an ultrasound or mammogram), and finally a core needle biopsy (where a small sample of the lump is removed for testing). These steps work together to ensure the most accurate diagnosis possible.
