PMC8247727_01
Knee MRI. T1w- coronal and sagittal planes.
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F1
Knee and thigh MRI [Figures 1 and 2] reports a supra-rotulian tumor, in the vast intermediate of the left thigh, with signals alterations of adipose tissue in the superior pole of the lesion.
Thigh MRI. T1-weighted-axial plane.
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F2
Knee and thigh MRI [Figures 1 and 2] reports a supra-rotulian tumor, in the vast intermediate of the left thigh, with signals alterations of adipose tissue in the superior pole of the lesion.
Left thigh tumor pathology: (a) HE x10: different areas were observed in the histological sections, some with a storiform pattern constituted with spindle, atypical, and polymorphic cells; also absence of differentiation and extensive necrosis. (b) HE x20: atypical lipogenic cells were found in neoplastic cells, constituting a component of pleomorphic liposarcoma. (c) HE x40 and (d) HE x60: they continued with well-differentiated liposarcoma cells, with desmoplastic stroma, abundant lipoblastic cells, and hyperchromatic and pleomorphic nuclei and presence of numerous mitoses. Diagnosis: high-grade sarcoma (Grade 3. French system combined score 7 (FNCLCC): tumor differentiation 3, mitosis 3-50 mitoses in 10 CGA -, necrosis 1). (Dedifferentiation of pleomorphic and well-differentiated liposarcoma).
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F3
Final staging: pT2b Nx Mx [Figure 3].
(a) T1w with gadolinium-saggital, (b) T1w with gadolinium-axial. (c) T2w coronal. (d) Diffusion sequence.
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F4
Proposing a cerebellar metastasis as the first option [Figure 4].
(a) Vimentin 20X (b) KI67 40X. Cerebellar tumor: Dedifferentiated tumor metastasis, sarcomatous in appearance with a fusiform pattern, marked nuclear atypia, high mitotic rate, compatible with previous tumor metastasis. In the immunohistochemical study, it only expresses vimentin, with the absence of expression of the S100 protein and also the gliofibrillar protein and liposarcoma markers.
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F5
Regarding the cerebellar lesion, pathology reports a dedifferentiated tumor metastasis, sarcomatous aspect with fusiform pattern, marked nuclear atypia, high mitotic rate, and compatible with previous tumor metastasis [Figure 5].