Open AccessMalignant transformation of salivary gland pleomorphic adenoma: proof of principle
Author(s) -
Valstar Matthijs H,
Mast Hetty,
Hove Ivo,
Moonen Laura R,
Balm Alfons JM,
Smeele Ludi E,
Koljenović Senada,
Dinjens Winand NM,
Velthuysen MarieLouise F
Publication year - 2021
Publication title -
the journal of pathology: clinical research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.849
H-Index - 21
ISSN - 2056-4538
DOI - 10.1002/cjp2.216
Subject(s) - pleomorphic adenoma , malignant transformation , frameshift mutation , malignancy , adenoma , carcinoma ex pleomorphic adenoma , pathology , parotid gland , chromosomal translocation , salivary gland , medicine , mutation , biology , cancer research , genetics , gene
Supposed risk of malignant transformation of salivary gland pleomorphic adenoma (SGPA) is an important reason for aggressive retreatment in recurrent pleomorphic adenoma (RPA). 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 an 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. Thus, this case not only shows malignant transformation of SGPA, but also demonstrates that molecular analysis can be of help in recognising malignancy in the rare instance of RPA.