Adenoid cystic carcinoma with myoepithelial predominance affecting maxilla and maxillary sinus.

Adenoid cystic carcinoma (ACC) represents less than 10% of all salivary gland tumors, rarely occurring centrally in the jaws. Herein we describe the case of a 36-year-old female patient presenting a painless swelling in the right maxilla, resulting in marked facial asymmetry. Intra-orally it was observed a swelling covered by an erythematous and irregular-surfaced mucosa, affecting the gingiva and crossing the midline of the hard palate. Imaging studies showed a mixed radiolucent-radiopaque lesion with ill-defined borders, involving the right side of the maxilla and the maxillary sinus. Incisional biopsy revealed basophilic cribriform tumoral islands and solid sheets of neoplastic cells invading bone trabeculae. Most of the tumoral cells presented myoepithelial characteristics, while few true luminal/epithelial cells were observed. To illustrate the epithelial-myoepithelial pattern, immunohistochemical reactions were performed, as well as double immunohistochemical staining. The diagnosis was intraosseous ACC, which features were discussed as well as the potential differential diagnosis.

Ki67/KIT double immunohistochemical staining in cutaneous mast cell tumors from Boxer dogs.

Cutaneous mast cell tumors (MCTs) are among the most frequent malignant tumors in dogs and Boxer breed dogs have a higher incidence of this disease. Ki67 staining and KIT staining are widely used to predict natural behavior in canine MCT but no previous study has evaluated double staining of these proteins as a prognostic factor. Based on biological behavior predictors in canine MCT, the purpose of this study was to determine the Ki67 proliferative index in KIT positive cells using double stain immunohistochemistry technique. Sixty-nine MCTs from Boxer dogs were selected and a tissue microarray was constructed for the double stained immunohistochemistry. Double positivity (Ki67(+)/KIT(+)) was observed in 20/69 (29%) MCT, with a mean of 9.06 double positive cells per tissue core (range 0.48%-43.97%) and Ki67(-)/KIT(+) animals had a longer survival time than Ki67(+)/KIT(+) animals (p=0.03).