PMC9112973_01
Upper row: MRI showing tumor straddling across the petrous apex from middle fossa to the posterior fossa. (a) Tumor is hypointense on T1, (b) hyperintense on T2, and (c) showing contrast enhancement. (d) Note the bony erosion of the petrous apex without any calcification. Lower row: (e-h) serial MR images in the follow-up showing tumor with similar size on volumetric analysis.
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F1
Radiology showed lesion extending from the cerebellopontine angle to the middle cranial fossa straddling across the petrous apex with its erosion [Figure 1a-d]. Sequential MRI showed no increase in size or change in character of lesion [Figure 1e-h].
(a) MR images showing enlargement of tumor on T1, (b) T2, (c and d) sequences with areas of cystic changes and irregular contrast enhancement.
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F2
However, in the past 6 months, she presented with features of pseudobulbar palsy (severe ataxia, difficulty in swallowing, change in voice, and spasticity) and the radiology showed significant increase in size of the lesion with brainstem compression and heterogeneous contrast enhancement [Figure 2a-d].
(a) Low magnification demonstrating tumor arranged in lobules with a prominent chondromyxoid matrix (H&E x100); (b) high magnification demonstrating closely packed lacunae containing mononucleate and few binucleate cells with pleomorphic nuclei (H&E x400); (c) malignant chondrocytes with hyperchromatic nuclei with a prominent chondromyxoid matrix. Occasional mitoses are noted (arrow) (H&E x400).
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F3
Histopathology confirmed chondrosarcoma Grade II [Figure 3].
(a) Diffuse and strong nuclear immune reactivity for S-100; (b) tumor cells were positive for vimentin while were negative for EMA (c) and pancytokeratin (d), (a-d) immunoperoxidase (x200).
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F4
Tumor cells were positive for S-100 and vimentin [Figure 4].