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Oral giant cell fibromas (GCFs) are found predominantly in Caucasians and rarely in other races. This retrospective study evaluated the clinicopathological features of 24 GCFs in Taiwanese patients. Methods: Twenty-four consecutive cases of oral GCF were investigated from 1987 to 2008. Clinical data and microscopic features were reviewed and analyzed. Results: The mean age of patients at the time of diagnosis was 29 years. Oral GCF occurred more commonly in patients between 11 and 40 years of age. There were 12 male and 12 female patients. The lesions were found more frequently on the tongue (8 cases) and gingiva (7 cases). The mean size of the lesion was 5.5 mm (range, 2–10 mm) in greatest dimension. GCF is misdiagnosed frequently as fibroma (19 cases) or papilloma (5 cases). All tumors were treated by total surgical excision and no recurrence was found after treatment. Microscopically, the GCF was a sessile or pedunculated mass covered with a thin layer of parakeratinized or orthokeratinized stratified squamous epithelium. The tumor was composed mainly of loose or dense fibrous connective tissue with well-formed capillaries and no inflammation. The consistent and diagnostic feature was the presence of large stellate giant cells, usually with one or two nuclei. Multinucleated giant cells were seen occasionally. These giant cells were most numerous in the connective tissue just beneath the epithelium. Conclusion: Oral GCFs show no significant sex predilection and occur in patients in the second to fourth decades of life. Usually, the lesions are < 1 cm in diameter and are found more frequently on the tongue and gingiva. GCF resembles fibroma or papilloma and is difficult to diagnose correctly at the first glance. All GCFs can be treated by conservative surgical excision without subsequent recurrence.

Odontogenic keratocysts (OKCs) are more aggressive and more osteolytic lesions than dentigerous cysts (DCs) and radicular cysts (RCs). Osteopontin (OPN) is related to cancer metastasis and bone destruction. Binding of OPN to its cell membrane receptors integrin αv and CD44v6 can enhance tumor cell motility, migration, invasion and spread. This study assessed the possible contribution of OPN, integrin αv and CD44v6 to the local aggressive behavior and osteolytic ability of OKCs. Methods: We used an immunohistochemical method to examine the expression of OPN, integrin αv and CD44v6 in tissue sections of 20 OKCs, eight DCs and 10 RCs. Results: We found strong cytoplasmic OPN immunostaining in lining epithelial cells of 8 of 20 OKCs but not in any DCs and RCs. Positive OPN staining was also noted in the subepithelial connective tissue of four OKCs with intraepithelial expression of OPN. Diffuse and strong membranous integrin αv staining was discovered in osteoclasts in all our tissue sections and in nearly all lining epithelial cells of DCs and RCs, but not in OKCs. In addition, diffuse and strong membranous CD44v6 staining was also observed in nearly all lining epithelial cells of OKCs, DCs and RCs. Conclusion: Binding of OPN to osteoclast cell membrane receptor integrin αv can activate the osteoclasts and increase their osteolytic activity. In addition, binding of OPN to OKC lining epithelial cell membrane receptor CD44v6 can enhance the motility, migration, invasion and spread of lining epithelial cells into the surrounding cancellous bone. Therefore, we suggest that the local aggressive behavior and high osteolytic ability of OKCs in the jawbone can be explained at least partially by high expression of OPN and CD44v6 in lining epithelial cells of OKCs and high expression of integrin αv in osteoclasts.

Central ossifying fibroma (COF) is the most common benign fibro-osseous lesion of the jaw. This retrospective study evaluated the clinical and histopathologic features of 28 COFs in Taiwanese patients. Methods: Twenty-eight consecutive cases of COF were collected from 1988 to 2006. The clinical data and microscopic features of these cases were reviewed and analyzed. Results: The mean age of patients at the time of diagnosis was 34 years. There were six male and 22 female patients. Twenty-six (93%) cases were found in the mandible and two (7%) in the maxilla. The most common sites for COFs were the molar region (17 cases, 61%), followed by the premolar (8 cases, 28%), and incisor/canine (3 cases, 11%) regions. Bone swelling or expansion (96%, 26/27) was the most frequent clinical presentation. Six (21%) COFs presented as a radiolucent lesion, 17 (61%) as a mixed lesion, and five (18%) as a radio-opaque lesion. No recurrence of the lesion was found after surgical excision in this series. Microscopically, COFs showed trabeculae of woven bone (25 cases) and/or lamellar bone (5 cases) and/or spherules of cementoid (19 cases) in a cellular fibrous connective tissue stroma. The stromal component was highly cellular in 21 cases, moderately cellular in seven cases, prominently vascular in 11, and collagenous in six. Conclusion: COFs occur more frequently in female patients and in those in the second to fourth decades of life. The most commonly affected site is the mandible, especially the molar region. The majority of COF lesions present as a well-defined, mixed lesion radiographically. Most COFs can be treated by conservative surgical excision without subsequent recurrence.

Oral verruciform xanthoma (VX) is an uncommon oral mucosal lesion. This retrospective study evaluated the clinical and histopathologic features of 15 oral VXs occurring in Taiwanese patients. Methods: Fifteen consecutive cases of oral VX were collected from January 1988 to December 2005. Clinical data and microscopic features of these cases were reviewed and analyzed. Results: The mean age of patients was 45 years (range, 18-79 years). There were eight male and seven female patients. Seven (46.6%) cases occurred on the gingiva, four (26.7%) on the tongue, and four (26.7%) on the buccal or vestibular mucosa. The greatest mean dimension of the lesions was 0.8 cm (range, 0.3-2.0 cm). Three patients had concomitant other oral mucosal lesions such as oral submucous fibrosis, squamous cell carcinoma, and erosive oral lichen planus. Microscopically, all specimens showed varying degrees of surface parakeratosis and the accumulation of numerous foam cells in the connective tissue papillae among uniformly elongated epithelial ridges. Individuals or aggregates of foam cells were also found underneath the epithelial ridges in nine (60%) cases. When the oral VX lesions were further classified into three types according to the microscopic surface architecture, seven (47%) lesions were of the verrucous type, three (20%) the papillary type, and five (33%) the flat type. All patients received surgical excision of the lesions and no recurrence was noted during follow-up of up to 18 years. Conclusion: Oral VXs occur more frequently in the fifth decade of life. The more commonly affected site is the gingiva. The treatment of choice for oral VXs is surgical excision. The prognosis is excellent and recurrence was not seen in this study. [J Formos Med Assoc 2007;106(2):141-147]