Case History:
Multilocular solid and cystic jaw mass.
What is most frequent mutation identified in this jaw lesion?
A. CTNNB1
B. BRAFv600E
C. PTCH1
D. SMO
Correct Answer: B. BRAFv600E
Discussion:
Ameloblastomas are slow growing benign odontogenic epithelial tumors with high recurrence rates. The fifth edition of WHO classifies them into five types: Unicystic, conventional, extraosseous/peripheral, adenoid, and metastasizing. The conventional type is mostly found in the mandible with the most frequent mutation BRAFv600E. It is further subdivided into histological subtypes with follicular subtype being the most common. They appear as islands consisting of central stellate like reticulum with peripheral palisading cells with reverse polarity in fibrous stroma. Treatment requires removal of bone more than 10 mm of the radiographic margin.
References:
Marilena Vered, Kehinde Emmanuel, Adebiyi Kristiina Heikinheimo et al. Ameloblastoma, conventional. In: WHO Classification of Tumours Editorial Board. Head and neck tumours [Internet]. Lyon (France): International Agency for Research on Cancer; (WHO classification of tumours series, 5th ed.; vol. 9). Available from: https://tumourclassification.iarc.who.int/chaptercontent/52/332
Case contributed by: Sabesan Balasinkam, M.D., Surgical Pathology Fellow