Fabrício Passador Santos

Intraoral Adult Rhabdomyoma: A Case Report

A case of adult rhabdomyoma is reported. The lesion is a rare benign tumor of skeletal muscle origin which occurs predominantly in the head and neck region. In the present case, the clinical diagnosis favored a benign salivary gland tumor. Histologically, the tumor was composed of large round, oval, and polygonal cells of varying size with abundant pale, eosinophilic, fine, granular cytoplasm with peripherally located nuclei. Immunohistochemically, the lesion was positive for muscle-specific actin, smooth muscle actin, desmin, S100 protein, and Massons trichrome. Electron microscopic examination confirmed the presence of numerous myofibrils. The lesion was treated by surgical resection. The clinical, histological, immunohistochemical, and ultrastructural features are discussed in this study.

Immunoexpression of growth factors and receptors in polymorphous low-grade adenocarcinoma.

BACKGROUND Polymorphous low-grade adenocarcinoma (PLGA) is a rare malignant tumor that usually arises in the minor salivary glands. Growth factors are cell-secreted peptides that regulate biological processes such as growth, proliferation, and differentiation. In salivary gland tumors, immunoexpression of growth factors and their receptors is associated with cell proliferation, malignant transformation, and tumor invasion. This study analyzed the expression of growth factors and receptors in PLGA, in other to better understand the mechanisms involved in the process of neoplastic cell proliferation and tumor progression. METHODS The expression of growth factors FGF-2, PDGF-A, PDGF-B and receptors FGFR-1, FGFR-2, PDGFR-α, and EGFR was analyzed in 24 PLGA samples in comparison with normal salivary glands, by immunohistochemistry. A semi-quantitative analysis determined cell positivity in all stained sections. Scores were assigned according to percentage of reactive cells: score 0 < 10%; score 1-10 to 25%; score 2-25% to 50%; score 3->50%. The level of significance was set at 5%. RESULTS Most of the growth factors and receptors, apart from FGFR-2, were significantly reactive in PLGA. Comparing to salivary acini, all of the reactive growth factors and receptors were significantly stronger in PLGA. Comparing to salivary ducts, the expression of FGF-2, PDGF-B, FGFR-1, and EGFR was significantly stronger in the nuclei and/or cytoplasm of the neoplastic cells. CONCLUSIONS The increased expression of the growth factors and receptors in the PLGA, compared to normal salivary glands, may be related to cell proliferation, somehow participating in the oncogenic process.

Solitary fibrous tumor of the hard palate: a rare entity in oral cavity

A case of solitary fibrous tumor is reported. Solitary fibrous tumor is a rare neoplasia characterized by the proliferation of fusiform cells of mesenchymal origin accounting for at least 2% of all soft tissue tumors. In this present case, the initial diagnosis was salivary gland tumor because of the location in the hard palate. Histologically, the tumor was composed by conjunctive tissue with proliferation of oval and fusiform cells. The immunohistochemical analysis was positive for CD34 and CD99. The lesion was treated by surgical resection. The clinical, imaging, histological and immunohistochemical data are discussed in this study. Keywords Solitary fibrous tumor; Oral cavity; Hard palate; Differential diagnosis.