Symmetrical palatal fibromatosis: An additional case report with immunohistochemical characterization

BACKGROUND: The term “symmetrical palatal fibromatosis” was recently suggested to designate bilateral palatal lesions presenting as typically broad, “mirror” images on the posterior lateral region of the hard palate. PURPOSE: We report an additional case of this as-yet poorly understood oral lesion in a 67-year-old male patient, with emphasis on differential diagnoses and immunohistochemical characterization. CASE REPORT: The histopathological examination demonstrated a hypocellular, fibrous connective tissue with prominent thick collagen bundles and few blood vessels. Scattered large, stellate, and sometimes binucleated fibroblasts were found. Immunohistochemistry was positive for vimentin and negative for smooth muscle actin, S-100, desmin, HHF-35, AE1-AE3, Factor XIIIa, CD68, and FOSL1. This is the second study to show the immunohistochemical profile, with emphasis in FOSL1, of an additional case of symmetrical palatal fibromatosis. CONCLUSIONS: We encourage further reports about this entity, especially in relation to immunohistochemical and molecular features, so far poorly described, but very important for better recognition of this entity. Key words:Palate, symmetrical palatal fibromatosis, desmoplastic fibroblastoma, immunohistochemistry.