Radiation-induced epithelial-myoepithelial carcinoma in a patient previously treated with mantle-field radiation therapy for Hodgkin lymphoma.

BACKGROUND: Radiation-induced salivary gland tumors are well described in the literature, with mucoepidermoid cancer being the most common histologic entity. Epithelial-myoepithelial carcinoma is a rare tumor accounting for <1% of all tumors in the salivary glands. METHODS AND RESULTS: We describe the first case of radiation-induced epithelial-myoepithelial carcinoma in the English-language medical literature. A 48-year-old man presented with right-sided mandibular pain and trismus, 25 years after mantle-field radiation therapy (RT) for Hodgkin lymphoma. He underwent excision of a right submandibular mass, which revealed a diagnosis of epithelial-myoepithelial carcinoma. Although typically a low-grade tumor, the histology revealed extensive necrosis and high mitotic activity. The patient required multiple resections and adjuvant therapy after multiple recurrences over a 4-year period. CONCLUSION: Reports of epithelial-myoepithelial carcinoma are relatively rare and this case highlights the importance of long-term follow-up and increased awareness of the risks of salivary gland tumors in this population.

The mammary myoepithelial cell.

Over the last few years, the discovery of basal-type mammary carcinomas and the association of the regenerative potential of the mammary epithelium with the basal myoepithelial cell population have attracted considerable attention to this second major mammary lineage. However, many questions concerning the role of basal myoepithelial cells in mammary morphogenesis, functional differentiation and disease remain unanswered. Here, we discuss the mechanisms that control the myoepithelial cell differentiation essential for their contractile function, summarize new data concerning the roles played by cell-extracellular matrix (ECM), intercellular and paracrine interactions in the regulation of various aspects of the mammary basal myoepithelial cell functional activity. Finally, we analyze the contribution of the basal myoepithelial cells to the regenerative potential of the mammary epithelium and tumorigenesis.

Transforming growth factor-beta signaling helps specify tumor type in DMBA and hormone-induced mammary cancers.

To determine the role of transforming growth factor-beta (TGF-beta) signaling in mammary development and tumor formation, we previously generated transgenic mice that expressed a dominant-negative form of the TGF-beta type II receptor (DNIIR) under the control of DNA regulatory elements from the metallothionein promoter (MT-DNIIR-28). In this report, we tested the hypothesis that loss of TGF-beta signaling in the mammary gland alters the development of chemically or hormonally induced tumors in mice. Four groups of mice were used in the study: wild-type and MT-DNIIR-28 mice on zinc with pituitary isograft, and wild-type and MT-DNIIR-28 mice on zinc with pituitary isograft treated with the carcinogen, 7,12-dimethylbenz[a]anthracene (DMBA). Tumor-free survival over time, tumor growth rate, and tumor pathology were measured. Statistically significant differences in tumor free survival over time or tumor growth rate were not detected in wild-type versus transgenic mice treated with DMBA. In contrast, tumor-free survival was significantly altered in transgenic mice that were treated with the pituitary isograft alone with MT-DNIIR mice developing tumors more quickly. Alterations in the types of tumors that formed in wild-type versus MT-DNIIR DMBA-treated mice were detected. In wild-type mice, tumors with squamous differentiation or bicellular adenomyoepitheliomas were most common. Adenomyoepitheliomas were not detected in transgenic mice. Furthermore, there was reduced staining for alpha smooth muscle actin and keratin 14, markers for myoepithelial cells, in the glandular portion of tumors in transgenic mice. The pathology of tumors induced by pituitary isograft alone was also markedly different in wild-type and transgenic mice. All the tumors classified from wild-type mice demonstrated some form of squamous differentiation, whereas squamous differentiation was not detected in the pituitary-induced transgenic tumors. The results suggest that TGF-beta acts as a tumor suppressor for hormone-induced cancers and that TGF-beta has a role in determining tumor pathology by regulating myoepithelial or squamous differentiation, maintenance, or transformation.

Myoepithelioma metastatic to the orbit.

PURPOSE: To report a case of myoepithelioma metastatic to the orbit in an 11-year-old boy. METHODS: Interventional case report. An 11-year-old white male with a history of resection of a left thigh mass 10 months previously presented with a painless, rapid swelling of the left upper eyelid. Computed tomography scan and incisional biopsy of the orbital mass were performed. RESULTS: Immunohistochemical stains of the tumor in the left orbit and the previously resected mass were consistent with myoepithelioma. As a result of widespread metastases, the patient died 4 months after initial presentation to the eye clinic. CONCLUSION: Myoepithelioma should be included in the differential diagnosis of neoplasms that can metastasize to the orbit in the pediatric age group.

Carcinoma basocelular con diferenciación mioepitelial / Basall cell carcinoma with myoepithelial differentiation

Presentamos un nuevo caso de carcinoma basocelular con diferenciación micepitelial en un varón de 71 años. La tumoración, de 2,5 cm, estaba localizada en el ala nasal izquierda. Se trataba de un carcinoma basocelular típico que infiltraba en profundidad, alcanzando el tejido muscular. En algunas áreas del tumor el citoplasma de las células neoplásicas se hacía homogéneo y eosinofilico, desplazando el núcleo a la periferia. Estas células eran idénticas a las llamadas células hialinas descritas en tumores mixtos y mioepiteliomas de glándula salival y piel. En el estudio inmunohistoquímico presentaban una franca positividad para la actína muscular específica (HHF35) y más débil para la desmína. Ultraestructuralmente la eosinofilia citoplasmática estaba determinada por la presencia de abundantes filamentos finos de tipo actína que desplazaban los escasos tonofilamentos a la periferia. Estas células cumplían todos los criterios para ser etiquetadas como mioepiteliales. En la literatura sólo se han descrito siete casos de carcinoma basocelular con esta peculiar diferenciación (AU)

Características citológicas por PAAF de carcinoma epitelial-mioepitelial de parótida / Cytoligic characteristics by fine-needle aspiration of epithelial-myoepithelial carcinoma of the parotid gland

El carcinoma epitelial-mioepitelial constituye aproximadamente el 1 por ciento de los tumores de glándulas salivales. Este tumor ha ganado reconocimiento tras su inclusión en la clasificación de los tumores de glándulas salivales de la OMS. Describimos el cuadro citológico de la PAAF de uno de estos casos, haciendo especial énfasis en el diagnóstico diferencial. En la revisión bibliográfica sólo hemos encontrado 15 casos descritos. El tratamiento de elección de esta neoplasia es la escisión quirúrgica amplia. La recurrencia local alta tras tratamiento quirúrgico adecuado plantea la posibilidad de un origen multicéntrico, como describimos en este caso (AU)

Tumor odontogénico epitelial calcificante (tumor de Pindborg): a propósito de un caso / Calciying epithelial odontogenic tumor (Pindborg tumor): a case report

El tumor odontogénico epitelial calcificante es una neoplasia odontogénica benigna muy infrecuente que fue descrita por primera vez por Pindborg en 1955. La literatura registra sólo unos 160 casos, lo que representa menos de 1 por ciento de todas las lesiones odontogénicas. Presentamos el caso de una mujer de 57 años de edad que consultó por crecimiento progresivo e indoloro del maxilar inferior, de varios meses de evolución. Se realizó una mandibulectomía parcial con resección completa de la lesión, emitiéndose el diagnóstico histológico de tumor odontogénico epitelial calcificante. Se comentan las características histológicas, inmunohistoquímicas y ultraestructurales del tumor, así como los principales aspectos de su histogénesis, diagnóstico diferencial, pronóstico y tratamiento (AU)

Myoepithelial carcinoma (malignant myoepithelioma): first report of an occurrence in the maxillary sinus.

AIM: We document for the first time the occurrence of a malignant myoepithelioma at a site other than within the major and minor salivary glands. METHODS AND RESULTS: A 67-year-old male presented with progressive symptoms and signs of a space-occupying lesion in the right maxillary sinus. An initial biopsy identified a malignant (myo)epithelial lesion and a radical maxillectomy was performed. Histology, supplemented by immunohistochemistry, confirmed the presence of a malignant myoepithelioma. CONCLUSION: Malignant myoepithelioma is a very rare tumour composed almost exclusively of myoepithelial cells and, to date, has only been described arising in the the major and minor salivary glands. A variety of tumours of salivary tissue have been reported within the head and neck area at sites outside the major and minor salivary glands, probably arising within accessory salivary tissue. We report the first case of a malignant myoepithelioma occurring in the maxillary sinus, also presumably arising in accessory salivary tissue in this location.

Análise da citodiferenciaçäo de linhagens celulares derivadas de adenoma pleomórfico e de mioepitelioma humanos de glândulas salivares: estudo comparativo dos elementos citoesqueléticos e da resposta dessas células à membrana basal reconstituída (Matrigel) / Cytodifferentiation analysis of cell lines derived from human pleomorphic adenoma and human myoepithelioma: a comparative study based on the expression of cytoskeletal components and on the response of these two cell lines to a reconstituted basement

Adenoma pleomórfico e mioepitelioma säo neoplasias de glândulas salivares que exibem aspectos clínicos e histológicos semelhantes. Para avaliar o estágio de diferenciaçäo das células de maior capacidade proliferativa dessas neoplasias, utilizamos linhagens celulares derivadas de adenoma pleomórfico (AP2) e de mioepitelioma (M1). Estudamos a expressäo de proteínas citoesqueléticas, os aspectos subcelulares e a resposta das linhagens à membrana basal reconstituída (Matrigel). Células AP2 mostraram imunomarcaçäo a vimentina e citoqueratina 14, enquanto que células M1 a vimentina, pan-queratina e actina de músculo liso. Estudo subcelular da linhagem AP2 revelou características de células pouco diferenciadas. Célula M1 mostraram aspectos subcelulares de fenótipo mioepitelial bem diferenciado, exibindo feixes de microfilamentos com adensamentos focais. Após uma semana envolvidas por Matrigel, células AP2 exibiram formaçäo de estruturas ductiformes e células M1 organizaram-se em cordöes celulares. Nossos resultados indicam que células AP2 exibem fenótipo epitelial glandular neoplásico pouco diferenciado, enquanto que células M1, fenótipo mioepitelial neoplásico bem diferenciado. Admitindo-se que o adenoma pleomórfico e o mioepitelioma resultem de proliferaçäo neoplástica de células do ducto intercalado de glândulas salivares, o adenoma pleomórfico originar-se-ia de células mais indiferenciadas e permissivas, enquanto que células já comprometidas com a diferenciaçäo no sentido mioepitelial dariam origem ao mioepitelioma

[Role of myoepithelial cells in the histogenesis of lobular breast cancer]. / O roli mioepitelial'nykh kletok v gistogeneze dol'kovogo raka molochnoi zhelezy.

Myoepithelial cells (MC) and their distribution in lobular carcinoma (LC) of woman (4 cases) and dog (3 cases) mammary gland were studied by indirect Coons' method using monospecific antiserum against smooth muscle myosin. The following types of MC distribution in the duct-lobular system were distinguished: strictly peripheral localization and close connection with a basal membrane in LC in situ; disorderly distribution among tumour cells and complete disappearance from solid complexes of the infiltrating LC. It is shown that the alteration of normal architectonics of lobular structure is followed by MC move along the basal membrane resulting in the appearance of poorly differentiated MC. These facts do not allow one to draw the conclusion on the tumour nature of poorly differentiated MC; the decrease of their differentiation might depend upon the substrate.

[Current theories on the nature of myoepithelial cells and their role in the morphogenesis of dyshormonal hyperplasia and breast neoplasms]. / Sovremennye predstavleniia o prirode mioépitelial'nykh kletok i uchastii ikh v morfogeneze disgormonal'nykh giperplazii i opukholei molochnykh zhelez.

An analysis of current concepts on the origin and potentials of neoplastic transformation of myoepithelial cells (MC) of the mammary glands is presented. The epithelial and smooth-muscle nature of these cells is discussed. The hypothesis of mixed (epithelial and myoepithelial) nature of mammary gland carcinoma and possibilities of neoplastic transformation of poorly-differentiated forms of MC are considered. Methods for identification of cells of the myoepithelial origin are described.