PMC6458660_01
PET/CT shows hypermetabolic focus in the soft tissues of the posterior left medial ankle (arrow).
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PET/CT showed a hypermetabolic focus in the soft tissues of the posterior left medial ankle (Figure 1).
Sagittal T1 MRI image, showing tibial nerve lesion (arrow head) and posterior tibial nerve (arrows) and tibia bone (T).
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T1 hypointense (Figure 2) with mixed T2 hyperintense (Figure 3) mass lesion noted in the posterior medial soft tissues of the distal tibia, which demonstrated intense enhancement and abuts the tibial nerve. This was measured approximately 2.2 cm in maximum craniocaudad dimension (Figure 4) and approximately 1.9 x 1.0 cm2 in maximum axial dimension (Figure 4).
Sagittal STIR (short-TI inversion recovery) image showing tibial nerve lesion with a longitudinal diameter of 22.3 mm, posterior tibial nerve (arrows), and tibia bone (T).
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T1 hypointense (Figure 2) with mixed T2 hyperintense (Figure 3) mass lesion noted in the posterior medial soft tissues of the distal tibia, which demonstrated intense enhancement and abuts the tibial nerve. This was measured approximately 2.2 cm in maximum craniocaudad dimension (Figure 4) and approximately 1.9 x 1.0 cm2 in maximum axial dimension (Figure 4).
Axial T2 MRI image showing a well-defined hyperintense tibial nerve lesion measuring 9.5 mm x 19.3 mm.
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T1 hypointense (Figure 2) with mixed T2 hyperintense (Figure 3) mass lesion noted in the posterior medial soft tissues of the distal tibia, which demonstrated intense enhancement and abuts the tibial nerve. This was measured approximately 2.2 cm in maximum craniocaudad dimension (Figure 4) and approximately 1.9 x 1.0 cm2 in maximum axial dimension (Figure 4).
Surgical exposure and dissection of tibial nerve. The mass is encapsulated together with the nerve.
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It was found that the tumor surface can be exposed and the whole tumor can be freed via blunt dissection from the vascular bundle posterior medial distal leg (Figure 5).
Tibial nerve schwannoma dissection from surrounding epineurium.
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Gentle dissection along the plane of the tumor capsule from the epineural layers allowed the tumor to be shelled out as a whole (Figure 6).
Schwannoma mass with size matching the measures in MRI.
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A well-encapsulated tumor and inactive nerve was dissected and separated from the active nerve (Figure 7).
S100 positive immunostaining of schwannoma with diffused dark brown-stained tumor cells (magnification x40).
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A few cells were immunoreactive to epithelial membrane antigen (EMA) (Figures 8 and 9).
H&E stain of schwannoma (magnification x100). Short fascicles of spindle cells with eosinophilic cytoplasm with syncytial appearance were found. These spindle cells were arranged in a vague palisade pattern. On immunohistochemistry, these spindle cells were immunoreactive to S100 protein.
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A few cells were immunoreactive to epithelial membrane antigen (EMA) (Figures 8 and 9).