Sclerosing mucoepidermoid carcinoma of the parotid gland

Although mucoepidermoid carcinoma is the most common primary malignancy of the salivary glands, the sclerosing morphologic variant of this tumor is extremely rare, with only 6 reported cases. As its name suggests, sclerosing mucoepidermoid carcinoma is characterized by an intense central sclerosis that occupies the entirety of an otherwise typical tumor, frequently with an inflammatory infiltrate of plasma cells, eosinophils, and/or lymphocytes at its peripheral regions. The sclerosis associated with these tumors may obscure their typical morphologic features and result in diagnostic difficulties. Tumor infarction and extravasation of mucin eventuating in reactive fibrosis are 2 mechanisms of formation that have been suggested as underlying this morphologic variant. We describe herein another case of sclerosing mucoepidermoid carcinoma that was diagnosed in a 44-year-old woman and review the relevant literature. Morphologic evidence in support of the mucin extravasation hypothesis was identified, as small pools of mucin were present throughout the tumor. However, there was no concentration of the mucin pools near the areas with the most viable tumor cells, which would have provided evidence for a temporal sequence that eventuates in lack of mucin in the most sclerotic regions.     

Oncocytic mucoepidermoid carcinoma of the trachea.

We report a rare case of an oncocytic mucoepidermoid carcinoma of the trachea, which presented in a 78-year-old woman with hemoptysis. Oncocytic cells comprised the majority of this low-grade lesion and demonstrated granular cytoplasmic phosphotungstic acid-hematoxylin staining as well as strong immunohistochemical reactivity to antimitochondrial antibody. Most tracheobronchial tumors with oncocytic change are carcinoid tumors. To our knowledge, this is the first oncocytic mucoepidermoid carcinoma of the trachea reported. This diagnosis was facilitated by histochemical and immunohistochemical studies.     

Dedifferentiation in low-grade mucoepidermoid carcinoma of the parotid gland

Mucoepidermoid carcinoma (MEC), a common malignant salivary gland neoplasm, is generally divided into low-, intermediate-, and high-grade types according to the histologic features. To our knowledge, the present report describes the first case of dedifferentiation occurring in a low-grade MEC. A 55-year-old man presented with a biphasic neoplasm of the right parotid gland composed of low-grade MEC and dedifferentiated high-grade anaplastic undifferentiated carcinoma. Immunohistochemically, carcinoembryonic antigen expression was restricted to the low-grade MEC portion. The Ki-67-labeling index was higher in the dedifferentiated component than in the low-grade component. On image cytometric analysis, the low-grade MEC was diploid, whereas the dedifferentiated carcinoma was aneuploid. Although the patient was alive 10 years after the initial diagnosis, the tumor has recurred twice, at 3 months and 7 months after the initial resection. It is important to recognize that dedifferentiation can occur in a low-grade MEC, similar to other low-grade salivary gland carcinomas.     

Oncocytic mucoepidermoid carcinoma of the parotid gland: report of a case with DNA ploidy analysis and review of the literature

A 44-year-old female presented with a painful mass in the left parotid gland. Histologic examination revealed the characteristic picture of oncocytic mucoepidermoid carcinoma (OMEC) composed mainly of sheets of oncocytic cells with uniform nuclei and eosinophilic cytoplasm, focally smaller epidermoid cells surrounding poorly formed glandular spaces, and a few cystic structures lined by well-differentiated mucous cells with intracytoplasmic mucin. Immunohistochemical staining with antimitochondrial antibody showed granular cytoplasmic positivity in oncocytic cells. The resulting histogram for DNA ploidy analysis was of diploid type. OMEC of the parotid gland is a recently described rare neoplasm. Only six cases have been previously reported in the literature. For an accurate approach in the management of patients, OMEC should be considered in the differential diagnosis of oncocytic lesions of the parotid gland, most of which are benign.     

Multiple unrelated chromosome abnormalities in a metastatic mucoepidermoid carcinoma of the parotid gland.

We describe cytogenetic findings in a poorly differentiated, metastatic mucoepidermoid carcinoma of the parotid gland. The tumor was characterized by multiple, unrelated chromosome abnormalities. Except for two small aberrant clones showing t(1;7) and t(2;15), respectively, all other abnormal cells showed unique, mostly structural rearrangements peculiar to each cell. No less than 34 different abnormal karyotypes were observed. A similar karyotypic heterogeneity was also described recently in squamous cell carcinomas of the head and neck.     

Clear cell mucoepidermoid carcinoma of the parotid gland: a case report

Clear cell variant of mucoepidermoid carcinoma of the salivary glands is rare. A 55-year-old male patient with recently growing left parotid mass underwent superficial parotidectomy. Although the dominant component of the tumor was composed of clear cells, mucin containing cells were also present. Histochemically, alcian blue stain supported intracellular mucin positivity. Immunohistochemically, p63 was positive. Based on the morphological, histochemical and immunohistochemical findings, the case was diagnosed as mucoepidermoid carcinoma, clear cell variant.     

Oncocytic cystadenoma of the parotid gland with tyrosine-rich crystals

A case of benign oncocytic cystadenoma with abundant intraluminal tyrosine-rich crystals involving the parotid gland is described.     

Oncocytic adenoma of the parotid gland with psammoma bodies

An unusual slow-growing tumor was found in the superficial lobe of the right parotid gland. It was multilobulated and encapsulated and consisted of sheets of epithelial oncocytes and minor foci of myoepithelium and ducts. Psammoma bodies were abundant. An antibody directed against keratin protein was localized in all tumor cells and in ductal but not acinar elements of adjacent parotid tissue. Ultrastructurally, the neoplastic cells proved to be ductal epithelial and myoepithelial oncocytes.     

Oncocytic variant of mucoepidermoid carcinoma of submandibular gland: an unusual clinical and morphological entity

In this case report we describe a rare tumor--Oncocytic variant of Mucoepidermoid carcinoma of the submandibular salivary gland with a review of the literature. Oncocytic metaplasia in salivary glands is a benign change that is associated with increasing age and also seen in a few salivary gland neoplasms', which include oncocytoma, Warthin's tumor, and the rare, oncocytic carcinoma. Oncocytic differentiation in mucoepidermoid carcinoma (MEC) is uncommon. Only twelve well-documented cases of oncocytic MEC have been reported previously all of which occurred in the parotid gland. To the best of our knowledge this is the first case of oncocytic mucoepidermoid carcinoma involving the submandibular salivary gland. The recognition of this entity is important, since most of the other primary oncocytic lesions of the salivary gland are benign.     

Oncocytic cystadenoma of the parotid gland with prominent signet-ring cell features

A case of distinctive benign cystadenoma of the parotid gland composed of several different morphological components is presented. The most conspicuous morphological component and the largest part of the neoplasm was represented by solid sheets of oncocytlc cells surrounded by myoepithelial cell layer. Most oncocytlc cells possessed large intracytoplasmic vacuoles with the nuclei displaced towards the periphery, Imparting them wlth a striking signet-ring cell appearance. The size of the intracytoplasmic vacuoles ranged from 4 to 50 pn. lmmunohistochemically these signet-ring cells lacked lmmunoreactivity for S-100 protein and cytokeratin but they strongly stained for anti-mitochondrial antibody 113–1. The present case illustrates an unusual, hitherto undescribed, morphological feature of benign onmcytic cystadenoma of the parotid gland.     

Oncocytic lipoadenoma of the parotid gland: Immunohistochemical and cytogenetic analysis

Salivary gland oncocytic lipoadenoma is an exceptional benign tumor composed of mature adipose tissue associated with a mixture of oncocytes. We report a case of oncocytic lipoadenoma showing sebaceous differentiation, and provide a cytogenetic analysis, which has not yet been described. A 64-year-old male developed a left parotid gland, well-encapsulated tumor measuring 3.5×3 cm², showing mature fat cells associated with oncocytic changes of epithelial components. Immunohistochemistry showed a dual epithelial population with ductal (positivity for AE1/AE3, CK19, CK7 antibodies) and basal-cell (positivity for p63, CK14, CK5,6 antibodies) differentiation in oncocytic areas. Moreover, oncocytic cells were stained with anti-alpha-1 antichymotrypsin antibody and phosphotungstic acid–hematoxylin staining. Molecular cytogenetic analysis showed a translocation t(12;14), resulting in structural rearrangement of the region framing the HMGA2 gene at 12q14.3. Such alterations in HMGA2 have been described in both lipomas and pleomorphic adenomas of the salivary glands.     

Undifferentiated carcinoma of parotid gland.

Two cases of undifferentiated carcinomas of the major salivary glands were studied using immunohistochemical techniques. Results showed that this entity was a high grade malignant neoplasm arising from the excretory duct. Despite the undifferentiated appearance multiple immunophenotypes were evident in both cases.     

Oncocytic lipoadenoma of the parotid gland with sebaceous differentiation. Study of its keratin profile

Oncocytic lipoadenomas of salivary gland are extremely rare tumors with only two previously reported cases. In this paper, we describe an additional example of oncocytic lipoadenoma showing sebaceous differentiation, a hitherto unreported occurrence. The tumor was encapsulated and measured 3 × 2.5 × 2 cm. Microscopically, the tumor comprised a mixture of oncocytes with “light” and “dark” cells intimately associated with mature adipose tissue. The oncocytes were positive for low molecular keratin, epithelial membrane antigen (EMA), and keratin 7, with only a small subgroup of cells expressing high-molecular-weight keratin, keratin 5/6, keratin 19, and p63. Terminally differentiated sebaceous cells were positive for EMA and keratin 14 only. Calponin and actins were negative, indicating a lack of myoepithelial cells in the tumor. The keratin profile and p63 expression of this oncocytic lipoadenoma suggest the presence of a dual cell population somewhat similar to the dual cell population described in some ultrastructural studies of pure salivary gland oncocytomas and may represent partial basal-cell differentiation. The presence and nature of a dual cell population in oncocytic neoplasms of salivary glands merit further investigation to confirm these observations.     

Sclerosing mucoepidermoid tumour of the parotid gland: report of a case

A case of a low-grade mucoepidermoid tumour showing an unusual pattern of extensive central keloid-like sclerosis is reported. The sparsity of tumour islands renders recognition of its neoplastic nature difficult. It is postulated that the sclerosis results from exaggerated post-inflammatory scarring due to extravasation of mucin from the tumour into the stroma.