5 Fibrous, Gingival, Lipocytic, and Miscellaneous Tumors
Fibroma (“Bite” or “Irritation” Fibroma, Fibroepithelial or Fibrovascular Polyp) and Giant Cell Fibroma
• Dome-shaped nodule or papule; may be white/keratotic, mucosa-colored or ulcerated and is seen in areas readily traumatized by biting (i.e., buccal mucosa, lateral tongue, and lower labial mucosa) or on gingiva(where plaque accumulates) (Fig. 5-1, A-D).
• Nodular proliferation of fibrous tissue is associated with variable vascularity, hyperparakeratosis or orthokeratosis, ulceration, inflammation, epithelial hyperplasia, or atrophy (Figs. 5-2 and 5-3); variable myxoid/mucinous change (Fig. 5-4); or entrapment of muscle (Fig. 5-5).
• Sclerotic fibroma (also called storiform collagenoma) has dense, hyalinized bands of keloidal collagen with a slight storiform pattern and stellate and fusiform fibroblasts with clefts between collagen fibers; lesions are occasionally positive for factor XIIIa and CD34 (Fig. 5-6).
• Giant cell fibroma exhibits papillary surface, epithelial hyperplasia forming spiky rete ridges; giant, stellate, multinucleated fibroblast-like cells that sometimes show cytoplasmic positivity for smooth muscle actin suggesting differentiation toward myofibroblasts; and keloid-like dense collagen. Mast cells are often present (Figs. 5-7 and 5-8) similar to fibrous papule of the nose.
• Young patients in second to fourth decades; nodular masses on the marginal gingiva, often maxillary anterior region; pink, erythematous, dusky purple, or ulcerated; may be painful and, if vascular, will bleed; underlying bone may show “saucerization” of bone (especially with giant cell granuloma) (Fig. 5-10)
FIGURE 5-10 A, Gingival fibroma with ulceration. B, Peripheral ossifying fibroma. C, Pyogenic granuloma with ulceration. D, Pyogenic granuloma of the mandibular ridge at extraction sites. E, Peripheral giant cell granuloma.
(B, Courtesy of Dr. Ian Cole, private practice, North Andover, Mass.; C, Courtesy of Dr. Jeffrey Freedman, private practice, Lexington, Mass.; E, Courtesy of Dr. Shelly Abramawitz, Children’s Hospital Boston, Boston, Mass.)
Pluripotent cells in the gingival tissues when traumatized or irritated (usually by accumulation of dental calculus or bacterial plaque, rough edges of restorations, or presence of implants) differentiate toward endothelial cells, fibroblasts, osteoblasts, or osteoclast-like cells, giving rise to four distinct histologic entities or combinations thereof. Estrogen and progesterone causes overexpression of vascular endothelial growth factor in granuloma gravidarum. See Table 5-1 and Figures 5-11 to 5-19 for histopathologic features.
• Parulis consists of a mass of edematous granulation tissue with many acute and chronic inflammatory cells and tracts lined by neutrophils (Figs. 5-20 to 5-22); they are often mistaken for mucoceles (which do not occur on the attached gingiva).
Giant cell fibroma
• Cellular proliferation of spindled fibroblast–like cells with ovoid nuclei that have dispersed chromatin, inconspicuous nucleoli; sometimes only subtle osteoid deposits or focal calcifications are present (see Fig. 5-15, A and B)
• Proliferation of mononuclear and multinucleated giant cells (osteoclast-like or foreign body type) usually in sheets; giant cells contain 10-20 nuclei in a central location; mitoses may be seen in mononuclear cells; fresh hemorrhage and hemosiderin deposits, especially beneath the grenz zone (see Figs. 5-18, 5-19)
FIGURE 5-13 Granuloma gravidarum. A, Lobular proliferation of capillaries, ulcerated. B, Proliferation of endothelial cells and dilated capillaries with slight hobnailing of nuclei. C, More cellular areas focally.
FIGURE 5-15 Peripheral ossifying fibroma. A, Mass of cellular fibrous tissue with superficial cementum deposition and bone deeper in the tissue. B, Cellular proliferation of fibroblast-like spindle cells with deposition of woven bone with osteoid rim. C, Deposition of cementum droplets. D, Cementum droplets with eosinophilic rim.
FIGURE 5-16 Peripheral ossifying fibroma. A, Nodule of fibrous tissue with abundant bone. B, Cellular proliferation of spindle cells forming osteoid and woven bone. C, Osteoid rimmed by layers of osteoblasts.
FIGURE 5-18 Peripheral giant cell granuloma. A, Lesion abuts the epithelium focally. B, Sheets of multinucleated giant cells and mononuclear cells in vascular stroma. C, Multinucleated giant cells and occasional mitoses in stromal cells.
FIGURE 5-19 Peripheral giant cell granuloma. A, Grenz zone present. B, Hemosiderin just beneath the grenz zone. C, Mixture of multinucleated giant cells and spindled mononuclear cells with hemorrhage. D, Multinucleated giant cells and spindled mononuclear cells.
FIGURE 5-21 Parulis. A, Edematous granulation tissue with linear spaces/tracts. B, Edematous granulation tissue with foamy macrophages and acute and chronic inflammation, often misdiagnosed as mucocele. C, Tract filled with neutrophils (arrows).
FIGURE 5-23 Infantile hemangioma of buccal mucosa. A, Proliferation of endothelial cells that surround minor salivary glands. B, Cellular proliferation of endothelial cells and capillaries with occasional mitoses (inset). C, Cytoplasmic positivity for glucose transporter-1 (GLUT-1).
(A, Courtesy of Dr. Harry Kozakewich, Harvard Medical School, Boston, Mass.)
Buchner A, Shnaiderman-Shapiro A, Vered M. Relative frequency of localized reactive hyperplastic lesions of the gingiva: a retrospective study of 1675 cases from Israel. J Oral Pathol Med. 2010;39:631-638.
Katsikeris N, Kakarantza-Angelopoulou E, Angelopoulos AP. Peripheral giant cell granuloma. Clinicopathologic study of 224 new cases and review of 956 reported cases. Int. J Oral Maxillofac Surg. 1988;17:94-99.
Ono A, Tsukamoto G, Nagatsuka H, et al. An immunohistochemical evaluation of BMP-2, -4, osteopontin, osteocalcin and PCNA between ossifying fibromas of the jaws and peripheral cemento-ossifying fibromas on the gingiva. Oral Oncol. 2007;43:339-344.
Diffuse/Multifocal Gingival Hyperplasia
• Seen in patients with poor oral hygiene and hormonal changes (e.g., puberty and pregnancy), and in patients on medications such as phenytoin, valproic acid, calcium channel blockers, and cyclosporine
• Diffuse, often slightly nodular enlargement of the gingiva of varying severity (Fig. 5-24, A and B); leukemic infiltrates may have a similar clinical appearance (see Fig. 5-24, C)
• Presence of pools of eosinophilic material (fibrin that is positive with phosphotungstic acid-hematoxylin) that fills the lamina propria should raise suspicion for ligneous gingivitis/periodontitis, a disorder of plasminogen activator deficiency (Figs. 5-27 and 5-28).