DOTATATE PET-avid clear cell stromal tumour of the lung with YAP1::TFE3 fusion: Report of first Australian case.

Abstract

Clear Cell Stromal Tumour of the Lung (CCST-L) is a recently recognised rare lung neoplasm, with only 19 cases reported in the current literature. Its histogenesis and pathogenesis remain largely unknown, however recent studies demonstrated the recurrent finding of YAP1::TFE3 fusion, highlighting its likely contribution to the pathogenesis. Currently, the diagnosis of CCST-L is confirmed with histological findings, exclusion of lineage-specific differentiation on immunohistochemical staining and molecular testing. With previous reports of progressive disease and mortality from distant metastasis, CCST-L posts the potential of rapid progression. Currently, no general consensus has been reached for the implication of neoadjuvant or adjuvant chemotherapy in CCST-L. Its rarity also presents the difficulty in obtaining long-term follow-up and prognostication data. We herein present the first Australian case of CCST-L with YAP1::TFE3 fusion and the first CCST-L case with DOTATATE avidity to extend our knowledge on this disease entity.