The value of fat-suppressed T2 or STIR sequences in distinguishing lipoma from well-differentiated liposarcoma.
The objective of this study was to evaluate the diagnostic value of fat-suppressed T2-weighted (FS-T2) images or short tau inversion recovery (STIR) imaging in distinguishing lipoma from lipoma-like subtype of well-differentiated liposarcoma. Spin-echo T1-weighted and STIR or fat-suppression T2-weighted sequences were performed in 60 lipomas and 32 lipoma-like well-differentiated liposarcomas, histologically proven, looking for thick septa or nodules in T1-weighted images and linear, nodular, or amorphous hyperintensities on FS-T2/STIR sequences. Fourteen lipomas (23.3%) showed thick septa and/or nodules on T1, whereas on FS-T2 or STIR sequences only seven (11.7%) displayed hyperintense nodules and/or septa. All well-differentiated liposarcomas contained these signs on FS-T2 or STIR sequences. The presence of hyperintense septa or nodules in a predominantly lipomatous tumor on FS-T2/STIR sequences helps to differentiate malignant tumors from lipomas. Employing the presence of hyperintense nodules and/or septa as criteria of malignancy specificity was 76.6% and sensitivity 100%. Overdiagnoses of well-differentiated liposarcoma can occur due to the presence of non-lipomatous areas within lipomas.
Galant
J
J
Servicio de Radiodiagnóstico, Hospital Universitario San Juan de Alicante, Ctra. Nacional 332 Alicante-Valencia s/n, 03550 San Juan de Alicante, Spain. galant_joa@gva.es
Martí-Bonmatí
L
L
Sáez
F
F
Soler
R
R
Alcalá-Santaella
R
R
Navarro
M
M
D000273:Adipose Tissue / Q000473:pathology; D016477:Artifacts; D003238:Connective Tissue / Q000473:pathology; D003937:Diagnosis, Differential; D005121:Extremities; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008067:Lipoma / Q000175:diagnosis* / Q000473:pathology; D008080:Liposarcoma / Q000175:diagnosis* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012983:Soft Tissue Neoplasms / Q000175:diagnosis* / Q000473:pathology