WHO Classification of Tumours Editorial Board. Soft tissue and bone tumours [Internet]. Lyon (France): International Agency for Research on Cancer; 2020. (WHO classification of tumours series, 5th ed.; vol. 3). Available from: https://tumourclassification.iarc.who.int/chapters/33.
Radioogical classification:
Characterisation of soft tissue tumours based on internal morphology and classification of adipocytic tumours
Bansal A, Goyal S, Goyal A, Jana M. WHO classification of soft tissue tumours 2020: An update and simplified approach for radiologists. European Journal of Radiology. 2021;143:109937-109937. doi:https://doi.org/10.1016/j.ejrad.2021.109937
MR imaging:
Classification of lesions based on MR signal characteristics on T2 weighted images
Bansal A, Goyal S, Goyal A, Jana M. WHO classification of soft tissue tumours 2020: An update and simplified approach for radiologists. European Journal of Radiology. 2021;143:109937-109937. doi:https://doi.org/10.1016/j.ejrad.2021.109937
Typical imaging features of certain soft tissue tumours: https://doi.org/10.1016/j.ejrad.2021.109937
| ENTITY | TYPICAL SIGN | DESCRIPTION |
|---|---|---|
| ‣ | Target sign | Central area of low signal intensity surrounded by hyperintense rim on T2W MRI |
| Fascicular sign | Multiple ring-like T2 hypointense structures in T2 hyperintense area representing fascicular bundles | |
| Split-fat sign | Presence of fat at upper and lower poles of lesion s/o intermuscular location | |
| ‣ | Chocolate-chip cookie sign | Presence of rounded or linear low signal intensity foci on T1 and T2 weighted images along with vigorous enhancement |
| ‣ | Bright cap sign | Thin rim of fat at superior and inferior poles of the lesion with brush-like surrounding edema |
| ‣ | Swirl sign and Lamellated/whorled appearance | T2 hyperintense lesion with Internal areas of whorled linear T1 and T2 hypointense signal |
| ‣ | Zone phenomenon | Lamellated peripheral/eggshell ossification with surrounding edema |
| ‣ | Triple sign | Intermixed areas of low, intermediate and high signal intensity on T2 weighted images |
| Bowl of grapes appearance | Fluid-fluid levels or areas of high signal intensity on T1 and T2 weighted images due to haemorrhage | |
| Nerve lipomatosis | Co-axial cable/spaghetti like appearance | Longitudinally oriented T1 and T2 hypointense nerve fascicles and fibrous tissue surrounded by hyperintense adipocytic component |
| ‣ | Lasagne sign | T1 and T2 isointense lesion interlaced with streaks of fat |
| ‣ | Fascial tail sign | Tapering marginal extension of tumour along fascial planes |
| Dark bands | T1 and T2 low-signal bands due to collagen | |
| T2-blackout effect | Low signal on DWI and ADC | |
| Staghorn sign | Intramuscular finger-like extensions | |
| ‣ | Skin tail sign | Tumour having a claw with adjacent skin |
| Myxofibrosarcoma/Undifferentiated pleomorphic sarcoma | MRI tail sign | Tapering marginal extension of tumour along fascia |
| ‣ | Blooming | Exaggerated dark signal on gradient-echo MR images due to hemosiderin |
Table 2Typical imaging features of certain soft tissue tumours.