Pleomorphic Adenoma With a TGFBR3 ‐ PLAG1 Fusion: A Rare Case Report

Introduction Pleomorphic adenoma (PA) is the most common salivary gland tumour and typically harbours gene fusions involving the PLAG1 and HMGA2 genes. Here we present a rare case of PA with a TGFBR3‐PLAG1 gene fusion. Case Report A 75‐year‐old female patient presented with a long‐standing right parotid lump. Core biopsy histology was suggestive of a PA but next‐generation sequencing revealed the presence of TGFBR3‐PLAG1 gene fusion which has been described as strongly associated with myoepithelial salivary carcinoma (MECA). Complete excision of the lesion confirmed that it was a PA with no evidence of malignancy. There is no evidence of recurrence 1 year after surgery. Discussion/Conclusion Although TGFBR3‐PLAG1 gene fusion is mostly associated with MECA, it may occasionally occur in PA. For the time being, final diagnosis and patient management must remain rooted in the comprehensive histological assessment and not solely rely on the underlying gene mutations/fusions.