Pathology and Differential Diagnosi

Pathology and Differential Diagnosis

Cut surfaces have a dense whitish-gray, glistening appearance (Figure 5). The irritation fibroma is comprised of a dense and minimally cellular stroma of collagen fibers arranged randomly or organized into interlacing fascicles (Figures 6 & 7). The stromal cells are bipolar fibroblasts with plump nuclei and fibrocytes with thin, elongated nuclei and minimal cytoplasm. As with keloids of the skin, the mucosal fibroma may be remarkably avascular, but areas of necrosis are not seen unless associated with overlying mucosal ulceration. Keloids do not, moreover, occur in the mouth.

Usually scattered, mature capillaries are found; often a few of these are dilated. In cases resulting from the slow fibrosis of granulation tissue or pyogenic granuloma, focal areas of edema and neovascularity may be seen in the midportion or lower third of the mass. Occasional lesions may still contain residual granulation tissue, prompting some pathologists to prefer the term fibrotic pyogenic granuloma. Such lesions may be indistinguishable from the angiofibroma of tuberous sclerosis.