Anomaly of chromosome 8q12 with slow growing mass on the left cheek in front of ear lobule

 # A patient presents with a slow growing mass on the left cheek in front of ear lobule. A sample is sent for gene analysis and cytogenic analysis reveals anomaly of chromosome 8q12. What is the diagnosis?

A. Mucoepidermoid carcinoma

B. Adenoid cystic carcinoma

C. Acinic cell carcinoma

D. Pleomorphic adenoma

The correct answer is D. Pleomorphic adenoma.

The cytogenetic abnormality of chromosome 8q12 is clearly indicative of Pleomorphic adenoma. 

Pleiomorphic adenoma is most commonly seen in the Parotid gland. 

PLEOMORPHIC ADENOMA 

• Synonym: Mixed tumor. 

• Histogenesis: Following are the possible origins: - Myoepithelial cell - Intercalated duct reserve cell 

• It is the most common tumor of salivary gland cell. - Constitutes > 50% of all salivary gland tumors. - Constitutes 90% of all benign salivary gland tumors. 

• It contains cells of pleomorphic origin (can differentiate into epithelial- ductal/ non-ductal and mesenchymal cells-chondral, myxoid, osseous cells) 

• Genetics: PLAG1 (Pleomorphic Adenoma gene) mapped to chromosome 8q12 may be responsible for pleomorphic adenoma. 

• Clinical features: - Benign tumor; It is a mixed tumor i.e., composed of both ductal and myoepithelial cells (as against monomorphic adenomas that are composed of only one cell type). - Parotid is the most common site overall; intraorally, palate is the most common site.