Evaluation of mast cells in periapical cysts, dentigerous cysts, and keratocystic odontogenic tumors.

BACKGROUND: Several cell types are associated with the development of cystic and tumoral odontogenic lesions. Among inflammatory cells, mast cells can be associated with their pathogenesis. The aim of this study was to analyze mast cells in periapical cysts, dentigerous cysts, and keratocystic odontogenic tumors. METHODS: Tissue sections were submitted to toluidine blue staining and immunohistochemistry with antibody anti-tryptase (clone G3). Mast cells were quantitated using Image-Pro Plus software to obtain the mean number of mast cells in three regions: epithelial, superficial portion of the fibrous wall and deep portion of the fibrous wall from 20 periapical cysts, 20 dentigerous cysts (six non-inflamed and 14 inflamed) and 20 keratocystic odontogenic tumors (four non-inflamed and 16 inflamed). RESULTS: The mean number of mast cells detected per lesion by immunohistochemistry (4.1) was higher than by histochemistry (1.5) (P<0.0001). Inflamed dentigerous cysts and keratocystic odontogenic tumors showed a higher mean number of mast cells than non-inflamed lesions in all regions. The deep region from all cysts showed the highest mean number of degranulated mast cells, except for non-inflamed keratocystic odontogenic tumors analyzed by immunohistochemistry. CONCLUSIONS: Immunohistochemical staining detected higher number of mast cells than histochemistry. The higher number of mast cells observed in inflamed lesions could indicate the participation of these cells in the inflammatory response in odontogenic lesions. The prevalence of degranulated mast cells in the deep region suggests intense activity of these cells, possibly related to growth of cystic lesions.

Expression of Bcl-2 family proteins and associated clinicopathologic factors predict survival outcome in patients with oral squamous cell carcinoma.

The aims of this study were to assess the expression levels of three proteins involved in apoptosis--Bcl-2, Bcl-X, and Bax--and evaluate their relationship with clinicopathologic features and survival in oral squamous cell carcinoma (OSCC). Immunohistochemistry was used to evaluate protein expression in 53 primary OSCCs treated by radical surgery with free margins at a single institution in 1999. Histologic specimens were graded and analyzed for perineural invasion, lymphocytic infiltrate, and pattern of invasion. Digital image analysis was performed to quantify immunostaining. Survival was analyzed using the Kaplan-Meier method and Cox's proportional hazard model. Cancer-specific 5-year survival (CSS) was 61% (56% overall survival (OS), and 51% disease-free interval (DFI)). Kaplan-Meier analysis identified pathologic stage (p=0.0007, log-rank test, OS), negative nodes status (pN) (p<0.0001, log-rank test, OS), presence of lymphocytic infiltrate (p=0.0084, log-rank test, OS), and high Bax expression (p=0.025, log-rank test, OS) to each be associated with both better OS and CSS. Tongue tumors (p=0.0179, log-rank test), worst pattern of invasion (p=0.0293, log-rank test), lack of lymphocytic infiltrate (p=0.0328, log-rank test), perineural invasion (p=0.0448, log-rank test), poorly differentiated tumors (p=0.0318, log-rank test), and low Bcl-X expression (p=0.044, log-rank test) were all associated with a low DFI. Cox regression found pN, lymphocytic infiltrate, and Bax expression to be independent prognostic factors for OS and CSS, whereas lymphocytic response and tongue tumors were predictors of DFI. Bcl-2 expression emerged as an independent marker of favorable CSS. Lymphocytic infiltrate was the most meaningful histopathologic parameter in survival analysis, whereas expression of Bcl-2 family members seems to be an important marker of a favorable prognosis in OSCC.

Erythrovirus B19 infection in acquired immunodeficiency syndrome: screening by histopathology, immunohistochemistry, and in situ hybridization.

Erythrovirus B19 infects erythrocytic progenitors, transiently interrupting erythropoiesis. In AIDS patients it causes chronic anemia amenable to treatment. We looked for evidences of B19 infection in stored bone marrow material from patients with acquired immunodeficiency syndrome. Histological sections were made from stored paraffin blocks from 33 autopsies (39 blocks) and 35 biopsies (45 blocks, 30 patients) performed from 1988 to 2002. They were examined after hematoxylin-eosin (HE) staining, immunohistochemical (IHC), and in situ hybridization. HE revealed intra-nuclear inclusion bodies ("lantern cells") suggesting B19 infection in 19 sections corresponding to 19 of 63 patients examined with this test. Seven of 78 sections subjected to immunohistochemistry were positive, corresponding to 7 of 58 patients examined with this test. Fourteen sections corresponding to 13 of the 20 HE and/or IHC positive patients were subjected to in situ hybridization, with six positives results. Among the 13 patients subjected to the three techniques, only one gave unequivocal positive results in all and was considered a true positive. The frequency of B19 infection (1/63 patients) in the material examined can be deemed low.