Page 62 - New epidemiological and PSMA-expression based paradigms in salivary gland tumors
P. 62

Chapter 4
 Abstract
Supposed risk of malignant transformation of salivary gland pleomorphic adenoma is an important reason for aggressive retreatment in recurrent pleomorphic adenoma. However, although the diagnostic category “carcinoma ex-pleomorphic adenoma” suggests that malignant transformation of a pleomorphic adenoma is a regular event, this has to date not been shown to occur in sequential lesions of one patient. Here we show the molecular events in transformation to malignancy of a pleomorphic adenoma of the parotid gland. Detailed molecular analysis revealed a LIFR/PLAG1 translocation characteristic for pleomorphic adenoma and, next to this, a PIK3R1 frameshift mutation and several allelic imbalances. In subsequent malignant recurrences the same LIFR/PLAG1 translocation, PIK3R1 frameshift mutation and allelic imbalances were present in addition to TP53 mutations. This case thus not only shows malignant transformation of salivary gland pleomorphic adenoma but also demonstrates that molecular analysis can be of help in recognizing malignancy in the rare instance of recurrent pleomorphic adenoma.
60































































































   60   61   62   63   64