ABSTRACT
Salivary gland neoplasms represent an important group of cancers in the head and neck and myoepithelial cells play a key role on the development these tumors. This study evaluated the distribution of mast cells and related proteins (PAR-2, TGFß1, IL-6) to the myofibroblastic differentiation in malignant tumors of salivary glands with and without myoepithelial differentiation. Immunohistochemical assessement for tryptase mast cells, SMA, PAR-2, TGFß1, IL-6 was performed in 10 cases of polymorphous low-grade adenocarcinoma, 14 cases of mucoepidermoid carcinoma (MEC) and 10 cases of adenoid cystic carcinoma. When the density of mast cells were compared between tumors, their density was significantly higher in MEC (P=0.08). Tumors with high expression of PAR-2 (79.4%) exhibited a high density of mast cells. Myofibroblasts were more frequent in malignant tumors with low expression (<50%) of cell masts. Individual analysis of the tumors showed no significant difference between the expression of PAR-2, IL-6, TGFß1, and myofibroblasts. When the density of mast cells, myofibroblasts and the expression of PAR-2 protein, IL-6, and TGFß1 were compared, it was no statistically significant difference between tumors with and without myoepithelial differentiation. The results of present study suggest a possible participation of mast cells and especially of PAR-2 in the development and progression of malignant salivary cancers, regardless of myoepithelial content.
Subject(s)
Cell Differentiation , Interleukin-6/metabolism , Mast Cells , Myofibroblasts , Neoplasm Proteins/metabolism , Receptor, PAR-2/metabolism , Salivary Gland Neoplasms , Transforming Growth Factor beta1/metabolism , Humans , Mast Cells/metabolism , Mast Cells/pathology , Myofibroblasts/metabolism , Myofibroblasts/pathology , Salivary Gland Neoplasms/metabolism , Salivary Gland Neoplasms/pathologyABSTRACT
Tumors traditionally classified as parachordomas are rare, usually indolent, soft tissue neoplasms. This case report describes a 6-year-old girl with a mass in her left forearm measuring 11 x 6 cm. Foci of moderate nuclear atypia and various areas of necrosis were found in the tumor. Lung metastases were detected 3 months after diagnosis. Immunophenotyping revealed a strong, diffuse expression of pancytokeratin, S-100 protein, vimentin, glial fibrillary acidic protein and focal expression of chromogranin A. This is the fifth documented report on cases of metastasized parachordomas. It is rare for these neoplasms to show such aggressive behavior; moreover, immunoreactivity to chromogranin A is unexpected in these tumors. The relationship between the so-called parachordomas and soft tissue myoepithelioma/mixed tumors is discussed, including the recently defined pediatric myoepithelial carcinoma.
