Fibromatosis of the Parotid Gland: A Case Report

A 51-year-old woman was presented with a palpable mass in the infraauricular area that had existed for 4-months. The mass from the superficial lobe of the parotid gland was 2.7 cm in the greatest dimension and was ill-defined with rubbery, homogeneous, and fibrotic appearance. Histologically, the lesion was infiltrative into the lobules of the paratid gland, and was composed of a proliferation of spindle or stellate cells with cellular and sclerotic areas. On immunohistochemistry, the cells were only positive for vimentin and focally for smooth muscle actin. Differential diagnosis from nerve sheath tumors and solitary fibrous tumors involving the parotid gland was emphasized.