Lipoblasts in Spindle Cell and Pleomorphic Lipomas: a Close Scrutiny

Publication date: Available online 23 May 2017
Source:Human Pathology
Author(s): Michael Michal, Dmitry V. Kazakov, Ladislav Hadravsky, Kvetoslava Michalova, Petr Grossmann, Petr Steiner, Tomas Vanecek, Valentina Renda, Saul Suster, Michal Michal
The presence and frequency of lipoblasts (LPB) in spindle cell lipomas (SCL) and pleomorphic lipomas (PL) has never been studied in detail on histologically, immunohistochemically and molecular genetically validated set of tumors. The authors investigated this feature by reviewing 91 cases of SCL and 38 PL. When more than three unequivocal LPB were found, the case was regarded as positive for the presence of LPB. All positive cases were then stained with CD34 and Retinoblastoma (Rb) protein antibodies and tested by FISH for MDM2 and CDK4 amplifications and the FUS gene rearrangements. The patients with SCL and PL containing LPB were 14 women and 47 men, the rest was of unknown gender. The cases usually presented as superficial, well-circumscribed soft tissue masses and most commonly occurred in the upper back and neck. CD34 was expressed in all cases, while Rb protein was consistently absent in all. Molecular genetic results, when available, were in concordance with the morphological diagnosis of SCL/PL. LPB were found in 37 (41%) cases of SCL and 25 cases of PL (66%). While in many cases they are inconspicuous, in some others they constitute a very prominent component of the tumor. It is important to be aware of this fact in order to avoid misinterpretation as liposarcoma.



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