Clinicopathological features of dedifferentiated liposarcomas with meningothelial-like whorls: report of six cases / 中华病理学杂志

ABSTRACT

Objective@#To investigate the histopathologic, immunohistochemical, molecular genetic characteristics of dedifferentiated liposarcomas with meningothelial-like whorls(DDLMW).@*Methods@#Six cases of DDLMW diagnosed at Jiangsu Province Hospital(the First Affiliated Hospital of Nanjing Medical University) from March 2012 to August 2018 were enrolled. The cases were analyzed by routine HE staining, immunohistochemistry(MDM2, CDK4 and p16) and fluorescent in-situ hybridization(FISH) on MDM2 gene. Related literatures were also reviewed.@*Results@#Three of the 6 patients were male.The patient ages ranged from 40 to 77 years (mean, 58 years). Four tumors occurred in the retroperitoneum and two in the mediastinum. Histologically, the tumors showed, in addition to foci of well-differentied liposarcoma, characteristic, scattered meningothelial-like concentrical whorls. The whorls were composed of tightly, concentrically arranged, spindle to ovoid cells with mild to mederate cytological atypia. Metaplastic bone was present within or in their immediate vicinity in four case. The tumors cell also showed strong and diffuse immunoreactivity to MDM2, CDK4 and p16, but no immunoreactivity to S-100 protein, SMA, SOX10, EMA, CD21, CD23 or CD35. The Ki-67 labeling indexes were low, while FISH showed high levels of MDM2 amplification in all cases.@*Conclusions@#DDLMW is a rare morphologic variant of dedifferentiated liposarcoma. The whorls in DDLMW do not represent perineurial or follicular dendritic differentiation. Recognition and familiarity with its existence, as well as combined application of immunohistochemical staining and MDM FISH, are important to avoid confusion with other lesions.