Idiopathic gingival fibromatosis: description of two cases.

Gingival fibromatosis is an enlargement localized or generalized of the gingival tissue characterized by an expansion and accumulation of the connective tissue, predominantly type I collagen, with occasional presence of increased number of cells, supposed fibroblastic proliferation. Gingival fibromatosis can be induced as a side effect of systemic drugs, such as phenytoin, cyclosporin, and nifedipine, or due to hereditary factors. However, in some cases, the gingival overgrowth is idiopathic. This paper reports two cases of idiopathic gingival fibromatosis and discusses the diagnosis, histopathological features, treatment and immunohistochemical evaluation of myofibroblasts of this condition. The tissues removed were fixed in formalin, and sections used for hematoxylin and eosin and Masson tricromic stain. To determine the presence of myofibroblasts, we performed immunohistochemistry against a-SMA protein. Histological examination revealed epithelial hyperplasia with long rete pegs and increase in the dense fibrous connective tissue. The Masson tricromic stain revealed wide bundles of collagen strongly stained. It was showed negative labeling to a-SMA. These results strongly suggest that myofibroblasts are not involved in gingival overgrowth in the cases of IGF reported. Future studies will be necessary to determine the pathogenesis of idiopathic gingival fibromatosis.