A Distinctive Subset of PEComas Harbors TFE3 Gene Fusions

• DOI: 10.1097/pas.0b013e3181f17ac0
• Publication Date: 2010-09-21T11:30:34Z
• Authors: Pedram Argani; Sebastian Aulmann; Peter B. Illei; George J. Netto; Jae Ro; Hyun-yee Cho; Snjezana Dogan; Marc Ladanyi; Guido Martignoni; John R. Goldblum; Sharon W. Weiss
• Keywords: TFE3; Perivascular Epithelioid Cell; Lymphangioleiomyomatosis; Angiomyolipoma

Perivascular epithelioid cell neoplasms (PEComas) include the common renal angiomyolipoma, pulmonary clear sugar tumor, lymphangioleiomyomatosis, and less of soft tissue, gynecologic, gastrointestinal tracts. Recently, aberrant immunoreactivity for TFE3 protein (a sensitive specific marker harboring gene fusions) has been reported in as many 100% PEComas; however, status these not systematically investigated. We used a fluorescence situ hybridization (FISH) break-apart assay to evaluate evidence fusions archival material from 29 PEComas. These cases included 2 earlier published immunoreactive nonrenal PEComas, 14 additional 13 angiomyolipomas with predominantly spindle or morphology. Four PEComas (mean patient age 24 y) showed rearrangements by FISH, all 4 strong positive (3+) using original validated overnight incubation protocol. Two had adequate mRNA RT-PCR analysis, but neither harbored PSF-TFE3 fusion 1 PEComa. In addition, lung metastasis uterine PEComa amplification, an unreported phenomenon. None other 54 alterations, though exhibited moderate (2+) immunoreactivity. contrast, automated stainer, All genetic alterations immunolabeled strongly Cathepsin K, similar conclusion, subset lesions currently classified harbors fusions. Although numbers are small, distinctive features tendency young age, absence association tuberous sclerosis, predominant alveolar architecture cytology, minimal muscle markers, Despite significant morphologic immunohistochemical overlap may represent entity.