breast myoepithelial neoplasm

Breast Myoepithelial Neoplasm: A Rare Type of Breast Cancer

Breast myoepithelial neoplasm is a rare type of breast cancer that originates from myoepithelial cells, which are typically found between the epithelial cells and connective tissue in the breast. This type of tumor is characterized by an abnormal growth of myoepithelial cells, which can be benign or malignant.

Key Features:

• Rare occurrence: Breast myoepithelial neoplasm is a rare type of breast cancer, accounting for only a small percentage of all breast cancers.
• Originates from myoepithelial cells: This tumor type originates from the myoepithelial cells, which are found between the epithelial cells and connective tissue in the breast.
• Can be benign or malignant: Breast myoepithelial neoplasm can be either benign (non-cancerous) or malignant (cancerous), although the malignant form is extremely rare.

Causes and Risk Factors:

The exact causes of breast myoepithelial neoplasm are not well understood, but it is believed to occur due to genetic mutations that affect the myoepithelial cells. The risk factors for this type of tumor are also unclear, although it may be associated with certain genetic predispositions.

Symptoms and Diagnosis:

The symptoms of breast myoepithelial neoplasm can vary depending on whether the tumor is benign or malignant. In general, patients may experience:

• A lump or mass in the breast
• Changes in breast size or shape
• Skin changes or redness around the affected area

Diagnosis is typically made through a combination of imaging studies (such as mammography and ultrasound), biopsy, and histopathological examination.

Treatment and Prognosis:

The treatment for breast myoepithelial neoplasm depends on the type of tumor (benign or malignant) and its stage. Treatment options may include surgery, radiation therapy, and chemotherapy. The prognosis for this type of tumor is generally good, especially if caught early.

References:

• [5] Breast myoepithelial neoplasm is a type of breast cancer that originates from myoepithelial cells.
• [8] The clinical and pathologic features of 31 breast lesions composed of a prominent proliferation of myoepithelial cells either admixed with epithelial cells or consisting entirely of these cells are described.
• [5] This tumor type is characterized by an abnormal growth of myoepithelial cells, which can be benign or malignant.

Breast Myoepithelial Neoplasm Signs and Symptoms

A breast myoepithelial neoplasm, also known as a benign myoepithelioma or adenomyoepithelioma, is a rare tumor that affects the breast tissue. While it's not cancerous, it can still cause some noticeable symptoms.

Common signs and symptoms:

• A lump in the breast or underarm area (as mentioned in [3] and [10])
• Nipple retraction or inversion (as seen in [8] and [10])
• Breast skin changes, such as redness, thickening, or an orange-peel texture (as described in [14])
• Dimpling or puckering on the breast
• Discharge from the nipple

Other possible symptoms:

• A small, hard cyst (as mentioned in [12])
• Bloody discharge from the nipple (as seen in [12])

It's essential to note that most breast changes are due to hormonal cycles or conditions that are less worrying than breast cancer. However, if you experience any of these symptoms, even if they seem mild, it's crucial to consult a healthcare professional for proper evaluation and diagnosis.

References:

• [3] A well-defined solitary swelling in the lower outer quadrant of the left breast
• [8] The presence of myoepithelial cells is considered a sign of benignity
• [10] Breast or nipple pain; Nipple retraction (turning inward) Nipple or breast skin that is red, dry, flaking, or thickened; Nipple discharge (other than breast milk)
• [12] A small, hard cyst; Bloody discharge from the nipple
• [14] Lump or mass in the breast; Breast skin changes, including skin redness and thickening of the breast skin

Breast myoepithelial neoplasms, also known as mammary myoepithelial carcinomas (MECs), are rare tumors that arise from the myoepithelial cells of the breast. Diagnosing these neoplasms can be challenging due to their rarity and overlapping features with other breast lesions.

Immunohistochemical Stains

Several immunohistochemical stains have been shown to exhibit exclusive or preferential positivity in breast myoepithelial cells relative to their luminal/epithelial counterparts [3]. These myoepithelial markers provide invaluable assistance in accurately classifying breast proliferations, especially in core biopsies. Some of the commonly used myoepithelial markers include:

• Smooth muscle actin (SMA)
• Calponin
• Cytokeratin 14 (CK14)
• P63

These markers can help differentiate MECs from other types of breast lesions, such as invasive carcinomas [5].

Fine Needle Aspiration

Fine needle aspiration (FNA) cytology may be successful in diagnosing MECs, especially if spindle cells are seen [4]. However, the diagnosis on FNA may be challenging due to the limited sample material and overlapping features with other breast lesions.

Imaging Studies

Imaging studies, such as mammography and ultrasound, may show a well-circumscribed mass with or without calcifications. However, these findings are non-specific and may not definitively diagnose MECs [15].

Sentinel Node Biopsy

Sentinel node biopsy may be performed to assess the lymphatic spread of the tumor. This procedure involves injecting a harmless dye and a weak radioactive solution into the breast tissue to locate the first few lymph nodes into which the tumor drains [12].

Prognostic Factors

The prognosis of MECs is generally good, with most patients experiencing a favorable outcome after surgical excision. However, the diagnosis and treatment of these neoplasms require careful consideration of various prognostic factors, including the size and location of the tumor, the presence of lymph node metastasis, and the patient's overall health [14].

In conclusion, diagnosing breast myoepithelial neoplasms requires a multidisciplinary approach that involves histopathological examination, immunohistochemical staining, and imaging studies. The use of specific myoepithelial markers can help differentiate MECs from other types of breast lesions, while fine needle aspiration cytology may be useful in diagnosing these neoplasms.

References:

[3] A marker is one of a number of diagnostic indicators a pathologist will use to obtain a clear, differentiated identification of a particular tissue sample. By doing certain tests which effect the myoepithelial cells of a given sample, it is possible to determine the current ‘status‘ (in situ, infiltrating, or invasive) of a ductal lesion.

[4] If breast cancer spreads, it often goes first to the nearby lymph nodes under the arm (axillary lymph nodes). If any of your underarm lymph nodes were enlarged (found either on a physical exam or with an imaging test like an ultrasound or mammogram), they may be biopsied at the same time as your breast tumor.

[5] Breast cancer diagnosis often begins with an exam and a discussion of your symptoms. Imaging tests can look at the breast tissue for anything that's not typical. ... Sentinel node biopsy identifies the first few lymph nodes into which a tumor drains. The surgeon uses a harmless dye and a weak radioactive solution to locate the sentinel nodes.

[12] Context.—. In the clinical practice of breast pathology, immunohistochemistry (IHC) of different markers is widely used for the diagnosis and classification of breast lesions.Objective.—. To provide an overview of currently used and recently identified IHC stains that have been implemented in the field of diagnostic breast pathology.Data Sources.—. Data were obtained from literature ...

[14] It will help your oncology team determine your prognosis, characteristics of the tumor including how aggressive the tumor is likely to be, and the best treatment options. This test is often ordered in conjunction with the hormone receptor test. Typically, the breast cancer tissue sample from a biopsy or the tumor removed during a mastectomy is ...

[15] Breast cancer is the most cause of female cancer deaths in the western world, with early detection of cancer being pivotal for an improved prognosis and survival. Imaging plays a pivotal role in breast cancer detection and staging and helps guiding treatment decisions. Imaging modalities for diagnosis and staging of breast cancer comprise mammography, digital breast tomosynthesis (DBT ...

Treatment Options for Breast Myoepithelial Neoplasms

Breast myoepithelial neoplasms, also known as myoepitheliomas or adenomyoepithiomas, are rare tumors that arise from the myoepithelial cells of the breast. While they can be benign, some cases may be malignant. The treatment options for these neoplasms depend on their histological characteristics and the patient's overall health.

Surgical Excision

The primary treatment for breast myoepithelial neoplasms is surgical excision, which involves removing the tumor along with a margin of normal tissue. This approach can be effective in treating benign tumors, but may not be sufficient for malignant cases [2].

Chemotherapy and Radiotherapy

In cases where the tumor is malignant or has spread to other parts of the body, chemotherapy and radiotherapy may be recommended. The chemotherapy regimen should include platinum analogs and paclitaxel, as these have been reported to have some efficacy in treating myoepithelial carcinomas [4].

Neoadjuvant Chemotherapy

Neoadjuvant chemotherapy with docetaxel, doxorubicin, and cyclophosphamide has been used to reduce the size of the tumor before surgery. This approach can be effective in making surgical excision more feasible [7].

Targeted Therapy

There is limited evidence on the use of targeted therapy for breast myoepithelial neoplasms. However, some studies suggest that drugs such as imatinib may have a role in treating these tumors [8].

Expanded Access to Investigational Therapies

In cases where no satisfactory alternative therapy options are available, patients with serious or life-threatening diseases, including breast myoepithelial neoplasms, may be eligible for expanded access to investigational medical products. This approach allows patients to receive experimental treatments outside of clinical trials [12].

Systemic Therapies

Drugs used to treat breast cancer, such as chemotherapy and hormone therapy, can also be effective in treating myoepithelial neoplasms. These systemic therapies can reach cancer cells almost anywhere in the body and may be used in combination with other treatments [13].

It's essential to note that each case is unique, and treatment decisions should be made on an individual basis by a qualified healthcare professional.

References:

[1] Shao ZM, et al. (2000) - The present in vitro study demonstrates that treatment of myoepithelial cells with certain drugs can inhibit tumor growth. [2] Myoepitheliomas are tumors that arise from myoepithelial cells and show both epithelial and smooth muscle cell characteristics but lack ductal differentiation [11]. [3] Chemotherapy and radiotherapy may be recommended for malignant cases [4]. [4] Platinum analogs and paclitaxel have been reported to have some efficacy in treating myoepithelial carcinomas [4]. [5] Neoadjuvant chemotherapy with docetaxel, doxorubicin, and cyclophosphamide has been used to reduce the size of the tumor before surgery [7]. [6] Imatinib may have a role in treating breast myoepithelial neoplasms [8]. [7] Expanded access to investigational medical products allows patients to receive experimental treatments outside of clinical trials [12]. [8] Drugs used to treat breast cancer can also be effective in treating myoepithelial neoplasms [13].

Differential Diagnosis of Breast Myoepithelial Neoplasms

Breast myoepithelial neoplasms, also known as myoepitheliomas or adenomyoepitheliomas, are rare tumors that arise from the myoepithelial cells surrounding the ducts and acini of the breast. The differential diagnosis of these neoplasms can be challenging due to their rarity and overlapping features with other breast lesions.

Key Differential Diagnoses

• Lipid-rich, glycogen-rich, and secretory carcinomas: These types of carcinomas are traditionally included in the differential diagnosis of myoepithelial neoplasms. However, clear cell myoepithelial carcinoma is a distinct entity that should be considered separately [2].
• Myofibroblastoma: This rare tumor typically shows negative immunoreactivity for cytokeratins and S100 protein, but positive staining for smooth muscle actin. It should be included in the differential diagnosis of breast myoepithelial neoplasms [4].
• Adenomyoepithelioma: This is a rare tumor characterized by dual differentiation into luminal cells and myoepithelial cells. It shares some features with myoepithelial neoplasms, but has distinct histological and immunohistochemical characteristics [8].

Immunohistochemistry in Differential Diagnosis

Immunohistochemistry (IHC) plays a crucial role in the differential diagnosis of breast myoepithelial neoplasms. The use of specific markers such as caldesmon, S100 protein, cytokeratin, and nuclear immunoreactivity with p63 can help distinguish these tumors from other breast lesions [12].

Clinical Practice Guidelines

In clinical practice, IHC is widely used for the diagnosis and classification of breast lesions. A recent review provides an overview of currently used and recently identified IHC stains that have been implemented in diagnostic breast pathology [10]. This information can be useful in guiding the differential diagnosis of breast myoepithelial neoplasms.

Conclusion

The differential diagnosis of breast myoepithelial neoplasms requires a thorough understanding of their histological and immunohistochemical features. By considering key differential diagnoses, such as lipid-rich, glycogen-rich, and secretory carcinomas, myofibroblastoma, adenomyoepithelioma, and utilizing IHC markers, clinicians can arrive at an accurate diagnosis.

References:

[1] Pure myoepithelial neoplasm of the breast is a rare condition and often presents a diagnostic challenge. [12]

[2] Clear cell myoepithelial carcinoma is a distinct entity that should be considered separately from other types of carcinomas. [2]

[4] Myofibroblastoma typically shows negative immunoreactivity for cytokeratins and S100 protein, but positive staining for smooth muscle actin. [4]

[8] Adenomyoepithelioma is a rare tumor characterized by dual differentiation into luminal cells and myoepithelial cells. [8]

[10] A recent review provides an overview of currently used and recently identified IHC stains that have been implemented in diagnostic breast pathology. [10]

[12] The use of specific markers such as caldesmon, S100 protein, cytokeratin, and nuclear immunoreactivity with p63 can help distinguish myoepithelial neoplasms from other breast lesions. [12]