MRI characteristics of parosteal lipomas associated with the HMGA2-LPP fusion gene.

Background: The magnetic resonance (MR) characteristics of parosteal lipomas with the HMGA2-LPP fusion transcripts are described.

Patients And Methods: The expression of HMGA2-LPP fusion transcripts was determined using the reverse transcription-polymerase chain reaction method.

Results: MR images of two cases with the fusion transcripts, a 56-year-old man and a 50-year-old woman, revealed heterogeneous high signal intensities on T1- and T2-weighted images, showing heterogeneous curvilinear enhancement on fat-suppressed T1-weighted images after Gd-DTPA injection, which resembled those of well-differentiated liposarcomas.

Conclusion: Since the HMGA2-LPP fusion transcripts are exclusively detectable in benign mesenchymal tumors, testing HMGA2-LPP expression may be useful for differential diagnosis in cases of radiologically-suspected well-differentiated liposarcomas.