Recurrent bilateral gingival peripheral calcifying epithelial odontogenic tumor (Pindborg tumor): a case report.

Calcifying epithelial odontogenic tumor (CEOT) is an extremely rare, benign neoplasm, accounting for approximately 1% of all odontogenic tumors. Peripheral CEOTs commonly resemble oral hyperplastic or reactive lesions and are histologically similar to their intraosseous counterparts. We report an unusual case of multifocal peripheral CEOT. A 40-year-old female presented with bilateral soft, painful, erythematous, gingival swellings localized in premolar areas of the mandibular gingiva. The presumptive diagnosis was bilateral pyogenic granuloma. The masses were surgically excised under local anesthesia without bone curettage and both recurred 12 months later. Morphologic features, and histochemical and immunohistochemical tests revealed bilateral peripheral calcifying odontogenic epithelial tumor. There is no clinical or radiographic evidence of recurrence 3.5 years after excision. This multifocal phenomenon has been reported previously only for intraosseous CEOT. Gingival masses must be carefully evaluated for clinical and histologic evidence of neoplasia.

Intravascular papillary endothelial hyperplasia: report of 4 cases with immunohistochemical findings.

Intravascular papillary endothelial hyperplasia (IPEH) is a benign endothelial proliferation, usually intravascular, that may mimic angiosarcoma. In this report, four new cases of IPEH involving the oral region are described. The affected sites were the lower lip, labial comissure and the submandibular region. After clinical evaluation, the complete removal of the lesions showed a circumscribed and soft mass. Histologically, the major feature was a reactive proliferation of endothelial cells composed of small papillary structures with hypocellular and hyalinized cores arising in an organized thrombus. Immunohistochemical staining for CD34 was strongly positive in endothelial cells. Vimentin and laminin immunolabelling were also consistent with a vascular origin. In order to verify the proliferative potential of the lesions, the Ki-67 antibody was used, revealing low percentage of labeled cells (<20%). No immunoreactivity for GLUT-1 was observed. Since the complete removal is curative, no additional treatment was necessary, and no signs of recurrence had been observed until now. Due to the particular features of IPEH, it is important for pathologists and clinicians to become familiar with this lesion. Additionally, the specific histological arrangement, including the absence of cellular pleomorphism, mitotic activity and necrosis, represents a guide to help in the differential diagnosis. Moreover, the vascular origin and the proliferative index should be assessed by immunohistochemistry in order to provide an accurate diagnosis.

Oral leiomyosarcomas: report of two cases with immunohistochemical profile.

Leiomyosarcoma of the oral cavity is a very rare tumor associated with aggressive clinical behavior and low survival. In this paper, we report 2 cases of leiomyosarcoma, affecting the gingival mucosa of a 54-year-old female and the maxillary bone of a 63-year-old male. Histologically, the tumors were composed of variably oriented fascicles of spindle-shaped cells with cigar-shaped nuclei and eosinophilic cytoplasm. The lesions were treated by surgical resection. Immunoreactivity to anti-vimentin, anti-smooth muscle actin, anti-desmin, anti-laminin, and anti-muscle-specific actin antibodies were found; conversely, the tumor cells were negative for anti-S100 and AE1/AE3 proteins. This report emphasizes the role of immunohistochemical study for correct diagnosis of leiomyosarcoma.

Immunolocalization of c-Fos and c-Jun in human oral mucosa and in oral squamous cell carcinoma.

BACKGROUND: Studies have addressed the relevance of c-Jun and c-Fos proteins in cancer development. In the present study, the expression of c-Jun and c-Fos, the major components of transcription factor activator protein (AP1), were evaluated to determine possible alterations to these factors in oral squamous cell carcinoma (OSCC). METHODS: Fifteen cases of normal oral mucosa and 20 cases of OSCC were retrieved from the Archives of the Surgical Pathology Service at the University of São Paulo. The samples of normal oral mucosa or OSCC originated from different oral mucosal sites. Tissues were submitted for immunohistochemical analysis to detect c-Jun and c-Fos proteins. The OSCC was classified as well, intermediate or poorly differentiated. RESULTS: The results showed that both c-Jun and c-Fos are expressed in normal oral mucosa and in OSCC. In normal mucosa, immunoreactivity for c-Jun was detected in the cytoplasm of the upper basal layers, while in OSCC, c-Jun was detected in the nuclei of the cells. C-Fos expression was observed in the nuclei of cells, both in normal mucosa and in OSCC, but its expression varied according to the cell layer in normal mucosa, and the differentiation of OSCC. CONCLUSIONS: The nuclear expression of c-Jun in OSCC, in contrast to its cytoplasmic expression in normal oral mucosa, indicates that c-Jun may have a role in the development of oral cancer. In contrast, the absence of both c-Jun and c-Fos in poorly differentiated carcinoma might be useful in understanding the cell cycle events important in uncontrolled cell growth.