Myxomas and myxoid liposarcomas of the extremities: Our preliminary findings in conventional, perfusion, and diffusion magnetic resonance

Abstract

Background The differentiation between myxomas and myxoid liposarcomas (MLPS) often is a serious challenge for the radiologists. Magnetic resonance imaging (MRI) is the most useful imaging technique in characterization of the soft tissue tumors (STT). Purpose To evaluate in a sample of myxomas and MLPS of the extremities, what morphological findings in conventional MRI allow us to differentiate these two types of myxoid tumors, in addition to analyzing the validity of the apparent diffusion coefficient (ADC) values of diffusion-weighted MRI (DW-MRI). Material and Methods Magnetic resonance imaging studies in myxomas and MLPS of extremities searched in our PACS between 2015 and 2019. All studies had conventional MRI with T1, T2, and PD SPAIR sequences, while DW-MRI with ADC mapping and perfusion MRI with a T1 sequence repeated for 4 minutes after contrast injection were additional sequences only in some explorations. Two radiologists evaluated independently the MRI studies by examining the qualitative parameters. Apparent diffusion coefficient values were calculated using two methods—ADC global and ADC solid, and Receiver Operating Characteristic (ROC) curves were applied for analysis. Results The features were consistent with MLPS: size greater than 10 cm, heterogeneous signal on T1, and nodular enhancement, while the common findings for myxomas were a homogenously hypointense signal on T1 and diffuse peritumoral enhancement. The solid and global ADC values were higher in myxomas. We observed that the solid ADC value less than 2.06 x 10−3mm2 x s would support the diagnosis of MLPS against myxoma. Conclusion Overall, MRI with its different modalities improved the diagnostic accuracy when differentiating myxomas from MLPS of extremities.

Fibrous dysplasia: A tale of two syndromes

“…Recent studies show that the evaluation of ADC values in DWI is useful to distinguish benign myxomas from myxoid liposarcomas, where higher ADC values support a more benign lesion. 5,9,16 Nuclear medicine has a limited role in intramuscular myxoma imaging with the majority of findings described on MRI. There is, however, mild to moderate F18-FDG avidity on PET-CT. 11 The most common complication of surgical excision of the myxomas is recurrence.…”

Myxoid Liposarcoma of the Breast Mimicking Phyllodes Tumor: A Case Report

“…Yabuuchi et al ( 9 ) showed that the apparent diffusion coefficient (ADC) decreased more in malignant phyllodes tumors than in benign phyllodes. Myxoid liposarcoma in the extremities also shows a lower ADC value than myxoma ( 10 ). Thus, both myxoid liposarcomas and phyllodes tumors are likely to have low ADC values.…”

Magnetic Resonance Imaging Biomarkers of Bone and Soft Tissue Tumors

“…53,54 However, of solid soft tissue tumors with high T2-weighted SI, authors have reported discrepant results on the efficacy of DWI and ADC mappings in differentiating benign from malignant myxoid soft tissue tumors, a particular histology to be aware of when assessing tumors with DWI. 40,[54][55][56][57][58] The assessment of treatment response in MSK lesions can benefit from DWI. 59,60 After chemotherapy or radiotherapy, neoplastic tissues typically lose cellularity and undergo necrosis or sclerosis.…”