Myoepithelioma of the head and neck, also myoepithelioma, is a salivary gland

tumour A neoplasm () is a type of abnormal and excessive growth of tissue (biology), tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tiss ...

of the

head and neck This article describes the anatomy of the head and neck of the human body, including the brain, bones, muscles, blood vessels, nerves, glands, nose, mouth, teeth, tongue, and throat. Structure Bones The head rests on the top part of the vertebr ...

that is usually

benign Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malig ...

. When malignant, which is exceedingly rare, they are known as malignant myoepithelioma or Myoepithelial carcinoma, and they account for 1% of the salivary tumors with poor prognosis. As the name suggests, it consists of

myoepithelial cell Myoepithelial cells (sometimes referred to as myoepithelium) are cells usually found in glandular epithelium as a thin layer above the basement membrane but generally beneath the lumen (anatomy), luminal cells. These may be positive for ACTA2, alph ...

s. Classically, they are found in the

parotid gland The parotid gland is a major salivary gland in many animals. In humans, the two parotid glands are present on either side of the mouth and in front of both ears. They are the largest of the salivary glands. Each parotid is wrapped around the m ...

palate The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly sep ...

. A similar tumor type may be found in the tongue, referred to as

ectomesenchymal chondromyxoid tumor Ectomesenchymal chondromyxoid tumor (ECT) is a benign intraoral tumor with presumed origin from undifferentiated (ecto)mesenchymal cells. There are some who think it is a Myoepithelioma of the head and neck, myoepithelial tumor type. Controversies ...

Pathology

The myoepithelial cells may be spindled, plasmacytoid, eithelioid or clear. Tubules or

epithelium Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of man ...

are absent, or present in a small amount (<5%) by definition. Tumours with myoepithelial cells and a large amount of tubules are classified as

pleomorphic adenoma Pleomorphic adenoma (or benign mixed tumor) is a common benign salivary gland neoplasm characterised by neoplastic proliferation of epithelial (ductal) cells along with myoepithelial components, having a malignant potentiality. It is the most comm ...

s (which must also contain the characteristic chondromyxoid stroma, which is normally absent in myoepithelioma).

Diagnosis

Myoepitheliomas are diagnosed from an examination of the tissue by a

pathologist Pathology is the study of disease. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in the context of modern medical treatme ...

. Image: Myoepithelioma - low mag.jpg , Low mag. Image: Myoepithelioma - high mag.jpg , High mag.

Treatment

Benign myoepithelioma are treated with simple excision. They are less prone to recurrence than pleomorphic adenoma. Malignant myoepitheliomas are excised and have been treated in the past with

dacarbazine Dacarbazine, also known as imidazole carboxamide and sold under the brand name DTIC-Dome, is a chemotherapy medication used in the treatment of melanoma and Hodgkin's lymphoma. For Hodgkin's lymphoma, it is often used together with vinblastine ...

but are prone to both

metastasis Metastasis is a pathogenic agent's spreading from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, ...

and re-occurrence.

References

External links

{{Medical resources , DiseasesDB = , ICD10 = , ICD9 = , ICDO = , OMIM = , MedlinePlus = , eMedicineSubj = , eMedicineTopic = , MeshID = Benign neoplasms Salivary gland neoplasia

Pathology

Diagnosis

Treatment

See also

References

External links