Clear-cell myoepithelial carcinoma of the salivary glands: a clinicopathologic, immunohistochemical, and ultrastructural study of two cases involving the submandibular gland with review of the literature.

Myoepithelial carcinoma (MC) is an uncommon neoplasm of the salivary glands, and cases of the clear-cell (CC) variant are extremely rare. Two cases of MC of the CC variant arising in the left submandibular gland are described herein. Both cases, which involved elderly women, almost exclusively consisted of large glycogen-rich CCs. Both cases were immunopositive for several epithelial and myoepithelial markers, and electron microscopy (EM) demonstrated hybrid epithelial and myoid differentiation in both. Case 1 arose in a pre-existing pleomorphic adenoma ("ex mixed tumor MC"), while Case 2 was a "de novo MC". CC-MC is an aggressive tumor with frequent recurrence, lymph node, and systemic metastases. A total of 14 cases of this type of neoplasm have been reported so far in the salivary glands, two arising from the submandibular gland. To date, only four cases have been studied using EM. The cases of CC-MC presented here are the third and fourth ones, respectively, originating from the submandibular glands, and the first two cases arising from this location, in which EM investigation succeeded in demonstrating myoepithelial differentiation. CC-MC needs to be distinguished from diverse primary and secondary CC neoplasms.

Carcinosarcoma ex Pleomorphic Adenoma of the Submandibular Gland in a 64-Year-Old Man: A Case Report.

Carcinosarcoma (CS) is a rare tumor, consisting of both carcinomatous and sarcomatous components. In this paper, we present a case of CS arising from a pleomorphic adenoma (PA) of the submandibular gland. A 64-year-old Japanese man presented with a left submandibular mass that had developed for 20 years with complaints of pain for the last 3 months. Magnetic resonance imaging showed a lesion involving the left submandibular gland. The patient underwent total dissection of the left submandibular gland and left cervical lymph nodes. Upon gross examination, the mass appeared completely covered by fibroadipose tissue measuring 46×42×45 mm; sectioning revealed a solid-white nodule with central bleeding and necrosis, invading into the surrounding adipose tissue. Microscopically, the presence of carcinomatous and sarcomatous components in the fibro-myxomatous stroma was detected, suggestive of pre-existing PA. The carcinoma component was diagnostic of salivary adenocarcinoma, not otherwise specified, whereas the sarcomatous component exhibited features of osteosarcoma characterized by formation of osteoid. As the border between the carcinomatous and sarcomatous components was not evident, CS may have occurred via transformation of the carcinoma into sarcoma. Tumor metastasis was detected in the cervical lymph nodes. Immunohistochemically, AE1/AE3 expression was noted in the carcinomatous component, but not in the osteosarcoma component. Both components were diffusely positive for vimentin. Four months after the operation, the patient developed a metastatic CS lesion in the lung, suggesting tumor aggression.

Head and Neck Extranodal Interdigitating Dendritic Cell Sarcoma: Case Report and Review of the Literature.

Interdigitating dendritic cell sarcoma (IDCS) is an exceedingly rare neoplasm originating from professional antigen presenting cells normally located in the T zone of the lymph node. The purpose of this report was to describe the first case of the IDCS of the submandibular gland and perform a review of the literature of head and neck IDCS. We present a case of an 81-year-old man with a 5 months history of slowly enlarging painless mass in right submandibular region. Fine needle aspiration cytology was suggestive of squamous cell carcinoma. The patient underwent surgical resection of the right submandibular gland and neck dissection. A malignant spindle cell proliferation involving the submandibular gland and colonizing one laterocervical lymph node was found. Morphology and immunophenotype prompted a differential diagnosis of a metastatic spindle cell melanoma versus an IDCS. Transmission electron microscopy was performed and supported a diagnosis of IDCS. The diagnosis of IDCS is a challenging task and may require a large array of techniques.

Histogenesis of benign pleomorphic adenoma (mixed tumor) of the major salivary glands. An ultrastructural and immunohistochemical study.

Twenty-two benign pleomorphic adenomas of the major salivary glands were studied by transmission electron microscopy and immunohistochemical techniques (three cases) in order to characterize the cell types comprising the epithelial and so-called mesenchymal regions of the tumors. Light- and electron-microscopic studies showed the tumors to consist of variable mixtures of neoplastic ductular epithelial cells, rare acinar cells, and metaplastic myoepithelial cells. Many of the loosely organized "stromal cells" contained structures indicative of their myoepithelial origin, e.g., perinuclear tonofilaments, ectoplasmic actin microfilaments, and remnants of basement membrane. Polyclonal antikeratin antisera strongly stained ductular epithelial and myoepithelial cells, squamoid cell nests, and periductular myoepithelial cells, whereas myxoid and chondroid cells were less intensely stained. Monoclonal cytokeratin antibody AE1 stained only the ductular epithelial cells in both the normal glands and tumors. In contrast, S-100 protein, which is present only in scattered acinar cells and myoepithelial cells in the normal parotid gland, was found in the ductular and periductular myoepithelial cells, isolated myxoid cells, and chondroid and cartilagenous cells in the tumors. Actin was found in all the cell types of the tumor but staining was strongest in the ducts. Double immunofluorescence staining for cytokeratin and vimentin revealed coexpression of both types of intermediate filaments in occasional normal acinar and intercalated duct myoepithelial cells, and in some cells in the myxoid and chondroid regions of the tumors. In the tumors, vimentin was present in occasional periductular myoepithelial cells, stellate myxoid cells, and especially in chondroid cells and chondrocytes. Our findings indicate that benign pleomorphic adenomas of the major salivary glands are pure epithelial cell tumors. The histologic complexity of these neoplasms is due to the ability of the neoplastic ductular myoepithelial cell to modulate its morphologic appearance and intermediate filament composition, and to produce large amounts of matrix substances. We further postulate that these tumors arise from neoplastically transformed intercalated ducts.

Malignant lymphoepithelial lesion of the submandibular salivary gland.

A case of malignant lymphoepithelial lesion (MLEL) occurring in the submandibular salivary gland of an Eskimo woman is presented. These unusual carcinomas have a striking frequency in Eskimos but are usually in the parotid gland. Cytology of fine-needle aspirated material demonstrated the cell type found by histologic examination. Electron microscopy confirmed a squamous differentiation of the malignant cells.

Malignant fibrous histiocytomas of salivary glands.

The light microscopic, immunohistological and ultrastructural findings in two cases of malignant fibrous histiocytoma arising in salivary glands are presented and the features of seven previously reported cases are reviewed. This neoplasm is extremely rare in this site and may pose problems in diagnosis. It has to be distinguished from other spindled cell tumours, in particular from epithelial tumours of predominantly spindled cell pattern; immunohistological markers for histiocytic cells may be of value. The histogenesis of this neoplasm is controversial but our electron microscopic findings support an origin from mesenchymal cells which differentiate along a broad fibrohistiocytic spectrum.

Characteristics of a rat fibrosarcoma-derived transplantable tumour line (SS) and cultured cell lines (SS-P and SS-A3-1) showing myofibroblastic and histiocytic phenotypes.

A transplantable tumour line (SS) was established in syngeneic rats from a spontaneous fibrosarcoma that had arisen in the submandibular salivary gland of a 24-month-old male F344 rat. A cell line (SS-P) was induced from SS, and a cloned cell line (SS-A3-1) was isolated from SS-P. The primary tumour consisted of oval to spindle-shaped cells arranged in bundles with abundant collagen fibres; ultrastructurally, neoplastic cells exhibited fusiform morphology with prominent rough endoplasmic reticulum. SS tumours showed marked interlacing fascicle and herring-bone growth patterns. SS-P and SS-A3-1 were similar morphologically to each other, consisting of oval, spindle or polygonal cells and occasional multinucleated giant cells. Tumours induced by SS-P and SS-A3-1 were histologically similar to SS tumours. Immunohistochemically, all cells in the primary tumour, SS tumours and tumours induced both by SS-P and SS-A3-1 and by SS-P and SS-A3-1 cultures gave a positive reaction to vimentin. Interestingly, neoplastic cells reacting to ED1 (rat macrophage/histiocyte-specific antibody) and alpha-smooth muscle actin (alpha-SMA) appeared in SS tumours and tumours induced by SS-P and SS-A3-1 and by SS-P and SS-A3-1 cultures. Cells with histiocytic fine structures and myofibroblastic cells with cytoplasmic actin-like microfilaments were also observed by electron microscopy. The present rat fibrosarcoma-derived transplantable tumour line (SS) and cell lines (SS-P and SS-A3-1) might express myofibroblastic and histiocytic phenotypes, probably depending on the surrounding conditions. These cell lines may prove useful for studying the mechanisms of phenotypic plasticity in neoplastic fibroblasts.

The congenital basal cell adenoma of salivary glands. Contribution to the differential diagnosis of congenital salivary gland tumours.

Congenital epithelial tumours of the salivary glands are very rare. The Salivary Gland Registry maintained in the Department of Pathology. University of Hamburg, contains only three cases among a total of 6,646 salivary gland tumours from the years 1965-1994. The three cases were classified as congenital basal cell adenoma, two of the parotid gland and one of the submandibular gland. Histologically, the three adenomas were similar in structure to the adult counterpart of basal cell adenoma with solid, trabecular or tubular (duct-like) patterns. In some cystic spaces of the duct-like structures PAS- and Astra blue-positive substances were secreted. On immunocytochemistry, the luminal duct-like cells showed membranous expression of cytokeratins 3, 5, 6, 7, 13 and 19. In the isomorphic basaloid cells of the solid and trabecular cell nests few cells expressed cytokeratin. On the outside of the solid cell nests there were smaller elongated myoepithelial-like cells, which expressed cytokeratin 14 and vimentin. Cytokeratins 1, 2, 4 and 18 were not expressed. The pattern of expression reflects the different stages of maturity of the tumour cells and is related to the development of the salivary glands until the end of the 3rd embryonal month with an arrest of further cell differentiation. No acinic cells, invasive growth, recurrence or metastases were observed. The differential diagnosis includes other congenital salivary gland tumours, such as hybrid basal cell adenoma-adenoid cystic carcinoma, sialoblastoma or embryoma, carcinoma, hamartoma and teratoma.

Characterization of epimyoepithelial islands in benign lymphoepithelial lesions of major salivary gland: an immunohistochemical and ultrastructural study.

Knowledge of the processes leading to the development of epimyoepithelial islands bears on histogenetic and morphogentic processes in salivary gland tumors. Immunohistochemical and ultrastructural investigations of the cellular composition of epimyoepithelial islands were carried out on three examples of benign lymphoepithelial lesions with varying histologic features. The monoclonal anti-keratin antibody 312C8-1, which specifically decorates myoepithelial cells of the normal salivary gland, also stains the myoepithelial cells surrounding residual acini and intercalated ducts in benign lymphoepithelial lesions and the cell population of epimyoepithelial islands, with the exception of persisting luminal epithelial cells. Ultrastructurally, the myoepithelial cells of involuting acini and ducts and the modified myoepithelial cells of epimyoepithelial islands, identified in both locations by the monoclonal antibody 312C8-1, show an increasing complement of tonofilament bundles. In addition, persisting lumens (often distended with lymphocytes) and definite luminal epithelial cells can be seen in electron micrographs of some epimyoepithelial islands. The designation for this characteristic epithelial feature of benign lymphoepithelial lesions is therefore appropriate.

Ultrastructural morphology of secretory granules in pleomorphic adenoma of human parotid and submandibular salivary glands.

Secretory granules were found in some of the cells lining the lumina of typical epithelial structures in pleomorphic adenomas. They were small, of varied electron density, and were mostly unipartite, sometimes bipartite and occasionally tripartite. They most closely resembled secretory granules of intercalary ductal cells of normal salivary glands.

Naturally occurring mucoepidermoid carcinoma in the submandibular salivary gland of two mice.

Mucoepidermoid carcinomas in two mice were investigated histologically, immunohistochemically and ultrastructurally. The neoplastic cells showed divergent differentiation into periodic acid-Schiff-positive mucous cells, keratin-positive squamous cells, and cells with both mucous granules and sheaves of tonofilaments. Gland formation and keratinization were not observed. At the periphery of tumour cell nests, some cells were immunolabelled for smooth muscle actin or contained concentrated thin filaments, and these observations were interpreted to indicate that murine mucoepidermoid carcinomas are associated with both myoepithelium and duct epithelium.

Basal cell adenocarcinoma of the submandibular gland.

Basal cell adenoma is a well recognized histopathologic variant of monomorphic adenoma of salivary gland, but in recent years there have been occasional reports of malignant basal cell tumors of major salivary glands. We present a case report of one such basal cell adenocarcinoma arising in the submandibular gland and discuss the differential diagnosis and distinction from a basal cell adenoma. We also review the published literature on basal cell adenocarcinoma. This is the first case of basal cell adenocarcinoma to be studied in detail by both immunohistochemistry and electron microscopy. There has been debate in the past as to the cell of origin of salivary gland basal cell tumors and specifically as to whether myoepithelial differentiation occurs in these tumors. The immunohistochemical and ultrastructural features of this case provide evidence for a dual population of ductal and myoepithelial cells. A flow cytometric analysis of nuclear deoxyribonucleic acid content showed the presence of DNA aneuploidy within one tissue block.

Merkel cell tumor-like neuroendocrine carcinoma associated with the submandibular gland. Report of a case with cytologic, immunohistochemical, electron microscopic and flow cytometric studies.

We report a rare case of primary Merkel cell tumor (MCT)-like neuroendocrine carcinoma (i.e., small cell carcinoma) associated with the submandibular gland in a 73-year-old man. Despite the lack of a known skin primary, the tumor exhibited cytomorphologic (predominant single cells with "intermediate filament buttons" in the background), ultrastructural (dense core granules and a globular aggregate of intermediate filaments) and immunohistochemical (paranuclear globular coexpression of cytokeratin and neurofilaments) features identical to that of MCT. The tumor contained an aneuploid peak with DNA index of 1.1 and an S phase of 20.5%. The tumor measured 5.8 cm and was situated between the skin and submandibular gland, with which it was closely associated but separated by connective tissue. The literature on MCT without a known skin primary is reviewed, and the cytomorphologic features that allow the distinction between MCT, lymphoma and oat cell carcinoma are discussed.

Multiple acinic cell carcinoma. Some histological and ultrastructural features of a case.

A case is presented of multiple acinic cell carcinoma, occurring synchronously in the left parotid gland and in the right submaxillary gland of a 75-year-old male patient. Fourteen cases of primary multiple acinic cell carcinoma have previously been reported, all bilateral parotid gland tumours. To our knowledge this is the first report of extraparotid localization of an acinic cell carcinoma in a patient presenting multiple salivary gland tumours. The histologic and ultrastructural characteristics of the tumours are described and a review of the literature is given.

Salivary duct adenocarcinoma: a high grade malignancy.

Salivary duct carcinomas of the major salivary glands have two major distinguishing features. They closely resemble ductal carcinomas of the breast and they are high-grade malignancies. In general, but particularly for carcinomas measuring three or more centimeters in size, the clinical course is one characterized by a resistance to local control, metastases to regional lymph nodes and distant sites, and death within a few years after primary surgical treatment.

Ancient schwannoma of the submandibular gland: a case report.

Schwannomas (neurilemmomas) are neurogenic tumors that arise from the Schwann cells of the neural sheath. They are most often benign and solitary. Extracranial schwannomas are rare, and can be mistaken for metastatic disease or other non-neurogenic tumors. Ancient schwannoma is a rare variant of schwannoma with a course typical of a slow-growing benign tumor. Histologically, it can be confused with a malignant mesenchymal tumor. An unusual case of an ancient schwannoma of the submandibular gland is reported. The clinical, histological and surgical aspects of this tumor are discussed, and the literature regarding this rare entity is reviewed.

[Neuroendocrine tumor of the submandibular gland. Report of one case and review of literature]. / Tumor neuroendocrino de glándula submaxilar. Presentación de un caso y revisión de literatura.

Report on one case of primary neuroendocrine tumor of the submandibularis gland, early detected without initial spread. Immunohistochemistry and electron microscopy were realized in order to determine the presence of intracytoplasmatic hypersecretory thick granules, these being the laboratory trials to differentiate between neuroendocrine tumors and undifferentiate carcinomata. Bibliographic review and proposal of classification of this sort of tumors.

Salivary duct carcinoma with rhabdoid features: report of 2 cases with immunohistochemical and ultrastructural analyses.

BACKGROUND: Salivary duct carcinoma with rhabdoid features is extremely rare. METHODS: We report 2 cases of salivary duct carcinoma with rhabdoid features treated at our institution. RESULTS: Case 1 was a 44-year-old Japanese man who had swelling in the left parotid region. This tumor consisted of residual pleomorphic adenoma and widely invasive carcinoma, which showed a diffuse growth pattern by atypical rhabdoid cells. Case 2 was a 66-year-old Japanese man who had swelling of the right cervical region. This submandibular tumor was also composed of both residual pleomorphic adenoma region and invasive adenocarcinoma components, whereas some metastatic lesions were purely composed of rhabdoid cells. Such cells were strongly and diffusely positive for cytokeratins (CKs), gross cystic disease fluid protein-15 (GCDFP), and androgen receptor (AR). Case 1 was also positive for Her-2 and p53. CONCLUSION: Both patients were diagnosed with carcinoma ex pleomorphic adenoma and their carcinomatous components were composed of salivary duct carcinoma with rhabdoid features, which is a highly aggressive tumor, similar to salivary duct carcinoma.

Mucinous adenocarcinoma of the submandibular gland.

A rare tumor not easily classifiable among published histologic categories for salivary gland tumors is reported. The neoplasm developed within the submandibular gland of a 78-year-old woman with invasion of the mandible and metastasis to regional lymph nodes. Histopathologically, cuboidal cells possessing clear cytoplasm and displaced round nuclei proliferated and exhibited an adenomatous pattern. Many cystic spaces surrounded by tumor cell strands were seen, mucus substance filled in the cystic spaces, and the tumor cells seemed mucus-secreting, but neither epidermoid cells nor papillary appearance could be observed. Electromicroscopically, numerous mucous droplets of low electron density were prominent in the cytoplasm, and the tumor cells had sparse irregular microvilli on the luminal surface. Mucin histochemistry, including paradoxical concanavalin A staining, revealed that the tumor cells contained neutral and acid mucins, and these were identified as class II and III mucosubstances. No other neoplastic lesion, except recurrent metastatic neck nodes, has been detected 6 years after the first examination, and it seems that the tumor is a rare primary mucinous adenocarcinoma of the submandibular gland.