P63 Expression Can Be Used in Differential Diagnosis of Salivary Gland Acinic Cell and Mucoepidermoid Carcinoma.
Ralph N Sams, Douglas R Gnepp. Alpert School of Medicine at Brown University Rhode Island Hospital, Providence, RI
Background: Differentiation of salivary gland acinic cell carcinoma from mucoepidermoid carcinoma can be diagnostically challenging as both may have prominent mucin production. P63 is a p53 homologue required for limb and epidermal morphogenesis. It is expressed in basal and myoepithelial cells of normal salivary gland tissues. In this immunohistochemical study, we examined the expression of p63 in salivary gland acinic cell and mucoepidermoid carcinomas and its use in differentiating these two entities.
Design: A search was performed and appropriate cases were selected from Lifespan Hospital System archives as well as the consult archives of one author (DG). 31 salivary gland acinic cell carcinomas (ACC) and 20 mucoepidermoid carcinomas (MEC) were examined for p63 expression by immunohistochemistry. The nuclear immunoreactivity was examined by both authors and was graded semi-quantitatively with negative being ≤5% cells staining, weak being >5 to <25% of cells staining, and strong being ≥ 25% of cells staining.
Results: Negative nuclear staining was seen in 30/31 (96.8%) of salivary gland ACC while 1/31 (3.2%) showed prominent nuclear staining. Strong positive nuclear staining was seen in 19/20 (95%) of salivary gland MEC cases while 1/20 (5%) cases showed minimal multifocal staining.
Conclusions: P63 is an immunohistochemical stain that can potentially aid in differentiating unusual acinic cell carcinomas with prominent mucin production from mucoepidermoid carcinomas of the salivary gland. According to this study, acinic cell carcinoma is almost always negative for p63 immunoreactivity while mucoepidermoid carcinoma is almost always strongly positive.
Category: Head & Neck
Wednesday, March 2, 2011 9:30 AM
Poster Session V # 143, Wednesday Morning