Malignant plasmacytoid myoepithelioma of the palate: histological observations compared to benign predominant plasmacytoid myoepithelial cells in pleomorphic adenoma of the palate

Myoepithelial Carcinoma Arising in a Plasmacytoid Myoepithelioma of the Parotid Gland Synchronized with Melanoma: A Case Report and Review of the Literature

Myoepithelial carcinoma, also known as malignant myoepithelioma, is considered an extremely rare (0.45-1%) malignant salivary gland neoplasm. Approximately 100 cases have been reported in the English-language literature on myoepithelial carcinoma. The majority of the myoepitheliomas described in the literature have been benign, and the malignant counterpart is considered rare (<1%). Such a tumor may appear de novo or rarely develop from a preexisting pleomorphic adenoma (<20%), and in exceedingly rare cases (<0.5%), it has arisen from a benign myoepithelioma (i.e., plasmacytoid myoepithelioma). To our knowledge, no case of myoepithelial carcinoma of the parotid gland arising in a plasmacytoid myoepithelioma synchronized with melanoma has been reported to date. The treatment of myoepithelial carcinoma has been mainly surgical, including wide excision with free margins, with or without nodal dissection. The roles of chemotherapy and radiotherapy have not yet been established. We report a case of myoepithelial carcinoma of the parotid gland arising in a plasmacytoid myoepithelioma synchronized with melanoma in a 40-year-old woman. In our case, a complete response was achieved with surgery followed by adjuvant chemotherapy based on carboplatin and paclitaxel concurrent with radiotherapy.

Malignant myoepithelioma of palate

Malignant myoepithelioma is a rare salivary gland neoplasm, which accounts for less than 2% of all the salivary gland carcinomas. Majority of cases have been reported in parotid, and only 8 cases of involvement of the hard palate have been reported in the literature so far. Hereby, a case of painless, ulcerated palatal mass of 2 years of duration reported. A diagnosis of malignant plasmacytoid myoepithelioma was made with the aid of immunohistochemical analysis, and wide surgical excision was considered keeping in mind the biological behavior of the tumor.

Radiotherapy in Malignant Myoepithelioma of the Soft Palate - Case Report

Myoepithelioma is a very rare neoplasm that accounts only for about 1% of all salivary gland tumours. As the lesion is so rare, there are no specific recommendations or guidelines for its treatment. In the literature, there have been only a few cases reported without any existing data concerning radiotherapy. We present a very good palliative effect of radiotherapy in a very old man.

Cystic clear cell myoepithelioma of the parotid gland. A case report

BACKGROUND

Myoepitheliomas of salivary glands are generally encapsulated, slowly growing asymptomic solid masses in which more than 50% are seen in the parotid gland. Cystic myoepitheliomas are very rare.

CASE REPORT

We present an 80-year-old man with a cystic mass in the right parotid gland that had undergone superficial parotidectomy. In gross examination, a mass containing a large cyst was observed. Microscopically, tumor consisted of clear cells and small cuboidal cells, forming tubules in a hyalinized stroma. Immunohistochemically, clear cells were immunoreactive for S100 and smooth muscle actin. Cuboidal cells were positive for cytokeratin. Diagnostic and differential diagnostic criteria were discussed under the light of the current literature.

From plasmacytoid to dendritic cell: morphological and functional switches during plasmacytoid pre-dendritic cell differentiation

Plasmacytoid dendritic cell precursors (pDC/IPC) are the major producers of type I interferon and have the unique ability to link innate and adaptive immunity. After producing large amounts of type I IFN in response to microbial stimulation, they can differentiate into DC capable of stimulating naive T cells and modulate the adaptive immune response. In this review, we focus on the transition between these two highly specialized cell types, which is accompanied by major morphological, structural and functional changes, many of which remain to be fully characterized. We propose that the plasmacytoid and dendritic morphologies correspond to distinct differentiation states and effector functions.

Ultrastructural changes of the palatal mucosa following application of 4-nitroquinoline-l-oxide (4NQO) in rats subjected to major salivary gland excision

OBJECTIVE

It has been suggested that saliva exerts a protective role against the carcinogenic effect of various substances in the oral cavity. The objective of this study was to examine the ultrastructural changes of the palatal mucosa caused by the application of 4-nitroquinoline-l-oxide (4NQO) in the presence or absence of saliva.

STUDY DESIGN

Wistar-Furth rats subjected and not subjected to total bilateral excision of the major salivary glands were either painted with an aqueous solution of 4NQO or with propylene glycol only (controls). Two animals of each group were humanely killed periodically. The areas of the palatal lesions were immediately sliced and processed for TEM examination.

RESULTS

Ultrastructurally, the progressive changes to squamous cell carcinoma were observed in the animals painted with 4NQO. In the desalivated animals group, the ultrastructural alterations appeared earlier than in the group with salivary glands.

CONCLUSIONS

Saliva appeared to delay but not hinder tumor induction by 4NQO.

Myoepithelial carcinoma of the salivary glands: a clinicopathologic study of 25 patients

Salivary gland carcinomas displaying exclusively myoepithelial differentiation (myoepithelial carcinoma) are considered rare. Their histopathologic features, immunohistochemical profile, and clinical behavior are not well characterized. The authors reviewed the clinicopathologic features of 25 salivary gland tumors fulfilling two fundamental histologic criteria: unequivocally malignant and exclusively myoepithelial. For most of these, the original diagnosis was malignant mixed tumor. Thirteen men and 12 women aged 24 to 77 years (mean age, 55 yrs) participated in the study, and most presented with a painless mass. The parotid gland was the most common site (n = 15). Tumors ranged from 2.1 to 5.5 cm, arising either in association with a benign mixed tumor (n = 15) or de novo (n = 10). Histologically, all the tumors displayed infiltrative growth and most had a characteristic multinodular architecture with a cellular periphery and central necrotic/myxoid zones. Epithelioid, hyaline, spindle, clear, or mixed cell types were noted with accompanying myxoid and/or hyalinized extracellular matrix. Ten tumors were high grade cytologically and 15 were low grade. The mitotic rate ranged from three to 51 mitoses per 10 high-power fields. Necrosis was present in 15 tumors and perineural and vascular invasion were identified in 11 and four neoplasms respectively. Immunoreactivities included CAM5.2 (89%), AE1:AE3 (100%), 34betaE12 (92%), cytokeratin 7 (21%), cytokeratin 14 (53%), vimentin (100%), S-100 protein (100%), smooth muscle actin (50%), calponin (75%), muscle-specific actin (31%), glial fibrillary acidic protein (31%), carcinoembryonic antigen (0%), and epithelial membrane antigen (21%). Ultrastructural examination of three tumors showed myoepithelial features. Ten patients developed recurrences, mostly multiple. Follow up of 17 patients showed that eight patients (47%) developed metastases (six high grade, two low grade) and five patients (29%) died of disease (four high grade, one low grade) after a mean of 32 months. Two patients were alive with disease (19 and 49 mos). Ten patients (59%) were without any evidence of disease after a mean of 42.2 months. Myoepithelial carcinomas exhibit a wide spectrum of cytomorphologic features and diverse clinical outcomes. As a result of their morphologic heterogeneity, they can be confused easily with many tumors. Myoepithelial carcinomas have been underrecognized in the past, primarily by being lumped under a broader category of "malignant mixed tumor." Awareness of their unique cytoarchitectural patterns and immunohistochemical profile is crucial for accurate identification.

Fine Needle Aspiration Biopsies of the Head and Neck: The Surgical Pathologist's Perspective

Masses of the head and neck comprise a variety of benign and malignant tumors and tumor-like conditions, which may present diagnostic challenges to the surgical pathologist and surgeon. Fine needle aspiration cytology is an increasingly popular technique in the initial evaluation of such lesions. The high diagnostic accuracy of this technique makes it generally preferable to traditional surgical biopsy. It is particularly useful in the sampling of histologically uniform neoplasms of the salivary glands, identification of classical papillary carcinoma and medullary carcinoma of the thyroid, separation of colloid goiter from follicular neoplasms, and confirmation of clinically suspicious lymph node metastases in cases with already documented malignant diseases. Despite its usefulness, aspiration cytology of head and neck lesions has certain inherent pitfalls, and these are briefly examined in this review. Int J Surg Pathol 8(1):17-28, 2000