A mismatch of tumor grade and biologic behaviour in a rare case of Sclerosing Mucoepidermoid Carcinoma of Parotid - with review of literature.

Although mucoepidermoid carcinoma is the most common primary malignancy of the salivary glands, the sclerosing morphologic variant of this tumor is extremely rare and only 26 cases have been reported till date in the english literature. This report describes a case involving a 35-year-old female with an intermediate-grade sclerosing mucoepidermoid carcinoma of parotid gland and we review the litreture. Immunohitochemical markers, Her-2/neu and MIB-1 evaluated to help predict the clinical outcome and to determine whether an association exists between the histologic grade and immunohistochemical findings. A PAS stain revealed cytic spaces filled with basophilic material. We found MIB-1 labeling indices of >50% and strong positivity for Her-2/neu suggesting poor prognosis. Our case did not show any correlation between MIB-1 index and tumor grade as shown in other case reports. This unusual but distinctive variant of mucoepidermoid carcinoma can be difficult to recognize and is frequently misdiagnosed as a benign lesion.