Abstract
Giant cell fibroma is an asymptomatic, fibrous polypoid lesion of the oral mucosa. Since only a few reports have appeared in Japanese literatures, the clinical, histopathological, and ultrastructural features of three cases of giant cell fibroma found in a 22-year-old female (gingiva), 44-year-old male (tongue) and 64-year-old female (tongue) are discussed. The lesions were characterized histologically by proliferation of stellate, mononuclear, and multinuclear giant cells surrounded by arcuate or sinuous bundles of collagenous connective tissue. A high rate of stellate and multinucleated giant cells were seen, in the increasing order, of 64-year-old male, 44-year-old male, and 22-year-old female. In 64-year-old male, the lesion contained somewhat dense fibrous tissues. Ultrastructurally, the giant cells were rich in well-developed endoplasmic reticulum and contained numerous microfibrils throughout the cytoplasm and in perinuclear areas. Sparsely distributed mitochondria, a few lysosome-like structures and free ribosomes-like granules were seen. Whorled collagen fibers were seen in the extracellular spaces. In areas of loosely arranged collagen bundles, numerous lysosome-like structures within the long cytoplasmic extensions of giant cells were seen. The giant cells showed many features similar to those of mononuclear or multinuclear fibroblasts.
