Intraosseous Schwannoma of the Calcaneus: A Rare Tumor of the Bone

Figure 2

(a) Histological examination reveals bundles of elongated cells with spindle-shaped nuclei between mature bone fragments (black arrows) (H&E ×10). (b) The hallmark of a schwannoma is the pattern of alternating Antoni A (black arrow) and B (white arrow) areas (H&E ×4). (c) Verocay bodies (black arrow), formed by two compact rows of well-aligned nuclei separated by fibrillary cell processes (H&E ×4). (d) Thickened hyalinized vessels (black arrow) are irregularly scattered in the lesion which are characteristic of schwannomas (H&E ×4). (e) Cytoplasmic and nuclear immunostaining of neoplastic cells with S-100 protein (magnification ×10). (f) Ki-67 proliferation index was observed around 5% at the highest level (magnification ×10).

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