PMC8422430_01
Convexity chondroma magnetic resonance imaging (MRI) and computerized tomography (CT) images. On the left and middle captions, T1- and T2-weighted MRI images reveal a dural attached convexity mass, well demarked from brain parenchyma and with no associated edema. No apparent invasion of calvarium diploe is noticed. On the right, a CT scan bone window highlights the calcifications inside the mass, responsible for the hypointense behavior in T1 and T2 MRI images.
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F1
The CT scan revealed a left frontal parasagittal mass of 4 cm x 4 cm x 2 cm molding the surrounding brain parenchyma, mostly isodense, with a large central calcification and hyperostosis [Figure 1]. Furthermore, the mass effect seemed to compress and reduce the lumen of the superior sagittal sinus [Figure 1].
Convexity chondroma on histology. Histopathological analysis reveals a monomorphous tumor of low cellularity. On the left and middle captions, we recognize chondrocytes without atypia embedded within a chondroid matrix. Immunohistochemically (on the right), neoplastic cells are S100 protein positive. In addition, they were vimentin positive and cytokeratin AE1/AE3, EMA, GFAP, and IDH1 negative (not shown). The Ki-67 labeling index was low (not shown).
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F2
The histopathologic analysis revealed a mass of cartilaginous tissue without cytologic atypia, confirming the diagnosis of dural chondroma [Figure 2].