A Rare Pulmonary Myoepithelial Tumor With Novel TRPS1-PLAG1 Fusions [post]

Qiang ZHENG, Shenglei LI, Qianming BAI, Xiaoyan ZHOU, Yue WANG, Yuan Li
2020 unpublished
Background: Little is known about the morphological and molecular features of intra-thoracic myoepithelial tumors. Here, we describe a rare pulmonary myoepithelial tumor with novel TRPS1-PLAG1 fusions.Case presentation: A 30-year-old male presented with multiple lung nodules that detected by routine computed tomography (CT) scan 3 years ago. Positron emission tomography-computed tomography (PET-CT) demonstrated a well-circumscribed mass with a diameter of 3cm in the left pulmonary hilum and
more » ... onary hilum and multiple nodules in bilateral lungs. No other extra-thoracic primary lesion and distant metastasis was found. The clinical history was not other specified. Microscopically, these lesions were well-defined, showed nodular growth pattern filling the bronchioles and alveoli. The tumor cells were epithelioid to plasmacytoid with slightly eosinophilic cytoplasm, arranged in aggregates, nests and cords. Myxoid background presented in some foci. Nuclear pleomorphism was mild and mitotic activity was not prominent. No distinct gland formation was identified. Immunostains demonstrated that the tumor cells were diffusely positive for pan-cytokeratin (AE1/AE3), CK5/6, S100, SOX10, and negative for calponin. Noticeably, a TRPS1-PLAG1 gene fusion was identified in this tumor by targeted RNA sequencing involved TRPS1 exon1 and PLAG1 exon2, this rare rearrangement was validated by fluorescence in situ hybridization (FISH) for PLAG1 break-apart probe, and 30% tumor cells showed break apart signals. Conclusions: Here we present the first case of a disseminated thoracic myoepithelial tumor with novel TRPS1-PLAG1 fusions. Targeted RNA sequencing strongly facilitates precise classification and providing opportunities for unknown fusion partner discovery, which is significant for risk stratification and development of potential therapeutic targets.
doi:10.21203/rs.3.rs-89835/v1 fatcat:44dgsfkaz5dhbfmymr3eiorram