Undifferentiated myxoid lipoblastoma with PLAG1-HAS2 fusion in an infant; morphologically mimicking primitive myxoid mesenchymal tumor of infancy (PMMTI)—diagnostic importance of cytogenetic and molecular testing and literature review

详细信息    查看全文

• 作者：Mikako Warren^a ; ¹ ; Brian K. Turpin^b ; Melissa Mark^b ; Teresa A. Smolarek^c ; Xia Li^c ; ^{Xia.Li@cchmc.org" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Lipoblastoma ; myxoid mesenchymal tumor ; cytogenetics ; PLAG1 rearrangement ; next generation sequencing
• 刊名：Cancer Genetics
• 出版年：2016
• 出版时间：January-February 2016
• 年：2016
• 卷：209
• 期：1-2
• 页码：21-29
• 全文大小：3351 K

文摘

Lipoblastoma is a benign myxoid neoplasm arising in young children that typically demonstrates adipose differentiation. It is often morphologically indistinguishable from primitive myxoid mesenchymal tumor of infancy (PMMTI), which is characterized by a well-circumscribed myxoid mass with a proliferation of primitive mesenchymal cells with mild cytologic atypia. PMMTI occurs in the first year of life and is known to have locally aggressive behavior. No specific genetic rearrangements have been reported to date. In contrast, the presence of PLAG1 (Pleomorphic Adenoma Gene 1) rearrangement is diagnostic for lipoblastoma. We hereby demonstrate the combined application of multiple approaches to tackle the diagnostic challenges of a rapidly growing neck tumor in a 3-month-old female. An incisional tumor biopsy had features of an undifferentiated, myxoid mesenchymal neoplasm mimicking PMMTI. However, tumor cells showed diffuse nuclear expression by immunohistochemical (IHC) stain. Conventional cytogenetic and fluorescence in situ hybridization (FISH) analyses as well as next generation sequencing (NGS) demonstrated evidence of PLAG1 rearrangement, confirming the diagnosis of lipoblastoma. This experience warrants that undifferentiated myxoid lipoblastoma can mimic PMMTI, and the combination of cytogenetic and molecular approaches is essential to distinguish these two myxoid neoplasms. Literature on lipoblastomas with relevant molecular and cytogenetic findings is summarized. Our case is the first lipoblastoma diagnosed with a PLAG1 fusion defined by NGS technology.