Pathology and Diagnosis
- Myoepithelial cells can be spindled, plasmacytoid, epithelioid, or clear.
- Tubules or epithelium are absent or present in a small amount (5%) by definition.
- Tumors with myoepithelial cells and a large amount of tubules are classified as pleomorphic adenomas.
- Pleomorphic adenomas must contain the characteristic chondromyxoid stroma, which is normally absent in myoepithelioma.
- The absence of tubules and chondromyxoid stroma helps differentiate myoepithelioma from pleomorphic adenoma.
- Myoepitheliomas are diagnosed through examination of the tissue by a pathologist.
- Diagnosis can be confirmed through low magnification examination.
- High magnification examination may be necessary for accurate diagnosis.
- Histopathological features specific to myoepithelioma aid in diagnosis.
- Immunohistochemical staining can be used to support the diagnosis.

Treatment
- Benign myoepitheliomas are treated with simple excision.
- They have a lower recurrence rate compared to pleomorphic adenomas.
- Malignant myoepitheliomas are also excised.
- In the past, dacarbazine has been used for treatment of malignant myoepitheliomas.
- Malignant myoepitheliomas are prone to both metastasis and recurrence.

Related Entities
- Pleomorphic adenoma is closely related to myoepithelioma.
- Ectomesenchymal chondromyxoid tumor is another related entity.
- Both pleomorphic adenoma and ectomesenchymal chondromyxoid tumor have distinct features distinguishing them from myoepithelioma.
- Understanding these related entities helps in accurate diagnosis.
- Comparative analysis of these entities contributes to the understanding of their pathogenesis.

References
- Barnes, L., Appel, BN., Perez, H., El-Attar, AM. (Jan 1985). Myoepithelioma of the head and neck: case report and review. Journal of Surgical Oncology, 28(1), 21–8.
- Wu, Tao; Lao, Zhiwei; Tang, Jun (1 January 2014). Myoepithelial carcinoma of the head and neck: A report of 23 cases and literature review. Cancer Treatment Communications, 2(2–3), 24–29.
- Smith BC, Ellis GL, Meis-Kindblom JM, Williams SB (May 1995). Ectomesenchymal chondromyxoid tumor of the anterior tongue. Nineteen cases of a new clinicopathologic entity. American Journal of Surgical Pathology, 19(5), 519–30.
- These references provide further insights into the characteristics, diagnosis, and treatment of myoepithelioma.
- They contribute to the existing literature and research on this topic.

Notable Points
- Pleomorphic adenomas must contain the characteristic chondromyxoid stroma, which is normally absent in myoepithelioma.
- Myoepitheliomas have a lower recurrence rate compared to pleomorphic adenomas.
- Malignant myoepitheliomas are prone to both metastasis and recurrence.