FIBROMATOSIS: A RARE BENIGN TUMOR IN THE FACE

Abstract

The 40-year-old white female patient complained of increased volume on face with no relevant past medical history. Extraoral physical examination showed painless volume increase in the right hemiface with 2 years of evolution, involving the parotid and masseter region, which was firm to palpation extending to the oral cavity without causing changes in the mucosa. Computed tomography scan of the face showed a calcified, multilocular, expansive lesion with precise limits invading chewing space on the right side causing erosion in the mandibular ramus. Incisional biopsy was performed, and the histologic slices in hematoxylin and eosin showed cellular proliferation infiltrating mucosa and skeletal striated muscle with nodular areas. Immunohistochemical analysis was positive for Ki-67, smooth muscle actin, and P16 and was negative for P63, ER, caldesmon, CD34, S100, desmin, and β-catenin. With the laboratory findings the diagnosis of fibromatosis was reached. Because of the impossibility of surgical resection, chemotherapy was started using tamoxifen, and the patient is being followed up. The 40-year-old white female patient complained of increased volume on face with no relevant past medical history. Extraoral physical examination showed painless volume increase in the right hemiface with 2 years of evolution, involving the parotid and masseter region, which was firm to palpation extending to the oral cavity without causing changes in the mucosa. Computed tomography scan of the face showed a calcified, multilocular, expansive lesion with precise limits invading chewing space on the right side causing erosion in the mandibular ramus. Incisional biopsy was performed, and the histologic slices in hematoxylin and eosin showed cellular proliferation infiltrating mucosa and skeletal striated muscle with nodular areas. Immunohistochemical analysis was positive for Ki-67, smooth muscle actin, and P16 and was negative for P63, ER, caldesmon, CD34, S100, desmin, and β-catenin. With the laboratory findings the diagnosis of fibromatosis was reached. Because of the impossibility of surgical resection, chemotherapy was started using tamoxifen, and the patient is being followed up.