PMC9516277_01
(A-D) A round iso-T1-long T2 signal nodule was located in the middle and lower third of the right sciatic nerve with significant enhancement. (E, F) A schwannoma of approximately 2.8 cm in diameter located in the sciatic nerve, with nerve bundle dilated with fluid and deformed by compression. (G) Hematoxylin and eosin staining showed schwannoma, Antoni A areas formed by closely packed tumor spindle cells, and loose mucus-like Antoni B areas, and no nerve fibers were visible in the tumor. (H) Immunohistochemistry showed that S-100 was scattered positive expression [original magnification (G, H), x100].
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Magnetic resonance imaging (MRI) showed a round-like nodule in the lower segment of the right sciatic nerve with iso-signal on T1-weighted images and hyper-signal on T2-weighted images with clear borders and the nerve trunk penetrating through it ( Figures 1A-C ). Contrast-enhanced examination showed significant enhancement of the tumor ( Figure 1D ). Ultrasound showed schwannoma located in the sciatic nerve ( Figure 1E ), with the nerve bundle dilated with fluid and deformed by compression ( Figure 1F ). Hematoxylin and eosin staining showed schwannoma and Antoni A areas formed by closely packed tumor spindle cells, and loose mucus-like Antoni B areas are seen; case 1 had no nerve fibers in the tumor ( Figure 1G ). Immunohistochemistry showed scattered positive expression of S-100 protein ( Figure 1H ).
PMC9516277_02
(A-D) A round-like iso-T1-long T2 signal nodule was located in the middle and lower third of the right sciatic nerve with progressive enhancement. The right sciatic nerve, tibial nerve, and common peroneal nerve trunk were extensively thickened, and the nerve bundles within them were thickened with a watery signal. (E, F) A gray-white nodule of 2.5-cm diameter with an intact envelope was seen on the incisional nerve epineurium. (G) Hematoxylin and eosin staining showed schwannoma, tumor spindle cells closely arranged in the Antoni A area, and nerve fibers visible in the tumor. (H) Immunohistochemistry showed scattered positive expression of S-100 protein [original magnification (G, H), x100].
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MRI showed a round-like nodule in the lower segment of the right sciatic nerve with iso-signal on T1-weighted images and hyper-signal on T2-weighted images with clear borders and the nerve trunk penetrating through it ( Figures 2A-C ). Contrast-enhanced examination showed progressive enhancement ( Figure 2D ). In the course of the operation, a marked thickening and limited enlargement of the right lower sciatic nerve were seen, and a grayish-white nodule with an intact envelope was seen on the incision of the nerve epineurium ( Figures 2E, F ). Hematoxylin and eosin staining showed schwannoma, tumor spindle cells closely arranged in the Antoni A area, visible nerve fibers in the tumor, nerve bundle membrane, and a significantly enlarged endothelial gap ( Figure 2G ). Immunohistochemistry showed scattered positive expression of S-100 protein ( Figure 2H ).