Malignant myoepithelioma of the soft palate

Benign myoepithelioma of the soft palate: an unusual clinical entity

Myoepitheliomas are rare benign tumours that affect the exocrine glands and are sporadically located in the salivary glands. The most common location of myoepithelioma in the oral cavity is the parotid gland and it is seldom encountered in the palate. The diagnosis of this entity is challenging since its clinical presentation may resemble those of more common neoplasms, rendering a complex histopathological diagnosis. The aim of the present case report is to describe an unusual case of myoepithelioma of the soft palate in a male patient, which developed as an asymptomatic, slowly growing mass. The tumour was assessed with histopathological examination and the diagnosis was verified via immunohistochemistry. Finally, the treatment included surgical resection of the tumour and no signs of recurrence were noted 2.5 years after the surgical procedure. Early diagnosis and treatment plays an important role in the prognosis of this pathological entity.

Benign myoepithelioma of the hard palate: a clinical and histological diagnostic challenge. Case report and literature review

Introduction: Myoepithelioma (ME) is a rare salivary gland tumor. Constructed aroung a clinical case, this article aims to gather up up-to-date epidemiological, clinical and histological data about myoeptihelioma with emphasis on the diagnostic approach and differential diagnoses, paraclinical exams and the main histological features reported for its characterization. Observation: A 41-year-old female, presenting a 1-year slowly enlarging palatine nodule was referred to the Oral Pathology Consultation. Clinical data and paraclinic examination were non-specific. A thorough histological examination, comparing clinical data with cyto-architectural and immunostaining profile of the tumor allowed a positive diagnosis of ME. Discussion: The clinical aspect of ME is close from other more frequent tumors within the same areas. Accordingly, its discovery is often incidental and its diagnosis histological. ME display variable architecture and composition, requiring full tumor examination for proper diagnosis. When benign, ME act as mixed tumor regarding local extension, prognosis and recurrence. Malignant ME behaves as a low-grade malignant tumor with metastatic potential. Conclusion: Despite its rarity, ME should be hypothesized in front of a palatine nodule. Clinician and pathologist should be particularly cautious regarding nature, malignancy and follow-up of this tumor, since few data are up-to-now available.

Invasive myoepithelial carcinoma ex pleomorphic adenoma of the major salivary gland: two case reports

BACKGROUND

Myoepithelial carcinoma (MEC) is a rare salivary gland tumor. Its long-term prognosis remains unknown because of the paucity of reported cases with long-term follow-up. Although some case series exist, the clinical features of MEC vary considerably depending on the site of origin. Therefore, accumulation of these rare cases is important.

CASE PRESENTATION

Case 1: An 89-year-old man presented with a 10-year history of a mass originating from the right parotid gland and involving the neck. The mass grew rapidly for 3 months, reaching approximately 8 cm. There was no facial paralysis. MEC ex pleomorphic adenoma (PA) was suspected. Superficial parotid gland resection was performed in 2013; the tumor grade was pT3N0M0, and the resection margins were free of carcinoma. Because of several high-risk factors for metastasis (i.e., invasive carcinoma ex PA, high MIB1 index, and mutant p53 protein positivity), radiotherapy and chemotherapy were recommended as adjuvant therapy. Although the patient refused adjuvant therapy, he was recurrence-free at 36 months after surgery. Case 2: A 54-year-old woman presented with a >10-year history of a right submandibular mass, which grew rapidly for 1 year, reaching approximately 6 cm. Preoperative diagnosis was PA of the right submandibular gland. Submandibular gland resection was performed in 2013. Pathological analysis revealed invasive MEC ex PA, pT3N0M0; in addition, the carcinoma portion had an extra capsule and had invaded the platysma muscle close to the margin. An MIB1 index of 40 % and mutant p53 protein positivity indicated a high risk for metastasis. Additional resection and right neck dissection revealed no residual carcinoma. The patient refused adjuvant chemotherapy. One year after surgery, metastasis to the right pulmonary hilar node and both lungs were detected. Chemotherapy prevented recurrent growth of the lesion and extended survival. The patient was alive with cancer 30 months after the first surgery.

CONCLUSIONS

High expression of the Ki67 labeling index might reflect prognosis of these cases. Chemotherapy for distant metastasis was effective, as expected. Further accumulation of cases and long follow-up data are needed to elucidate the pathophysiology and prognosis of MEC ex PA.

Salivary gland myoepithelial carcinoma

Salivary gland myoepithelial carcinoma (MC) or malignant myoepithelioma is a rare entity. MC usually presents as a slow-growing painless mass arising in the parotid gland, but may involve other salivary glands. This tumour may be particularly locally aggressive, but its clinical and biological features are not yet fully understood. MC may arise from pre-existing benign lesions, such as pleomorphic adenomas or benign myoepitheliomas, or may arise de novo. It usually affects patients over 50 years old, with no gender preference. Because it is often asymptomatic, the presentation and diagnosis can be delayed by months, even years. The current WHO classification considers MC to be an intermediate- to high-grade malignancy. Other published data suggest it is likely to be a high-grade neoplasm, consistent with its aggressive behaviour. Its epidemiology, histopathological features, immunohistochemical profile, clinical behaviour and optimal management are not well understood. Following review of the current literature we aim to address these.