title: Can Experienced Observers Differentiate between Lipoma and Well-Differentiated Liposarcoma Using Only MRI?
abstract: Well-differentiated liposarcoma represents a radiographic diagnostic dilemma. To determine the accuracy, interrater reliability, and relationship of stranding, nodularity, and size in the MRI differentiation of lipoma and well-differentiated liposarcoma, MRI scans of 60 patients with large (>5 cm), deep, pathologically proven lipomas or well-differentiated liposarcomas were examined by 10 observers with subspecialty training blinded to diagnosis. Observers indicated whether the amount of stranding, nodularity, and size of each tumor suggested a benign or malignant diagnosis and rendered a diagnosis of lipoma or well-differentiated liposarcoma. The accuracy, reliability, and relationship of stranding, nodularity, and size to diagnosis were calculated for all samples. 69% of reader MRI diagnoses agreed with final pathology diagnosis (95% CI 65-73%). Readers tended to err choosing a diagnosis of liposarcoma, correctly identifying lipomas in 63% of cases (95% CI 58-69%) and liposarcomas in 75% of cases (95% CI 69-80%). Assessment of the relationship of stranding, nodularity, and size to correct diagnosis showed that the presence of each was associated with a decreased likelihood of a lipoma pathological diagnosis (P < 0.01). While the radiographic diagnosis of lipoma or well-differentiated liposarcoma cannot be made with 100% certainty, experienced observers have a 69% chance of rendering a correct diagnosis.
authors.affiliation: Department of Orthopaedic Surgery, Markey Cancer Center, University of Kentucky, 740 S. Limestone Avenue, Lexington, KY 40536, USA.
authors.forename: Patrick W
authors.initials: PW
authors.lastname: O'Donnell
authors.affiliation: Department of Orthopaedic Surgery, Mount Sinai Hospital, Toronto, ON, Canada M5G 1X5.
authors.forename: Anthony M
authors.initials: AM
authors.lastname: Griffin
authors.affiliation: Department of Orthopaedic Surgery, Duke Cancer Center, Duke University, Durham, NC 27710, USA.
authors.forename: William C
authors.initials: WC
authors.lastname: Eward
authors.affiliation: Department of Orthopaedic Surgery, Mount Sinai Hospital, Toronto, ON, Canada M5G 1X5.
authors.forename: Amir
authors.initials: A
authors.lastname: Sternheim
authors.affiliation: Department of Orthopaedic Surgery, Mount Sinai Hospital, Toronto, ON, Canada M5G 1X5.
authors.forename: Lawrence M
authors.initials: LM
authors.lastname: White
authors.affiliation: Department of Orthopaedic Surgery, Mount Sinai Hospital, Toronto, ON, Canada M5G 1X5.
authors.forename: Jay S
authors.initials: JS
authors.lastname: Wunder
authors.affiliation: Department of Orthopaedic Surgery, Mount Sinai Hospital, Toronto, ON, Canada M5G 1X5.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Ferguson