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Soft tissue and bone tumors comprise a heterogeneous group of neoplasms ranging from benign lesions to highly aggressive sarcomas.
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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 |
RECIST 1.1 is a standardized guideline used globally to assess tumor response to treatment based on imaging techniques such as CT and MRI. It focuses on quantitative changes in tumor size to determine treatment effectiveness.
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ECIST 1.1 categorical thresholds and extrapolated volumetric thresholds. RECIST 1.1 = Response Evaluation Criteria in Solid Tumors version 1.1.
Gong AJ, Ruchalski K, Kim HJ, et al. RECIST 1.1 Target Lesion Categorical Response in Metastatic Renal Cell Carcinoma: A Comparison of Conventional versus Volumetric Assessment. Radiology. 2023;5(5). doi:10.1148/rycan.220166