PMC6767708_01
Intraoperative view of the right-forearm schwannoma. Full enucleation of
the schwannoma from the median nerve was readily achieved: the
nerve/tumor complex was isolated from the surrounding structures (a), a
well-defined cleavage plane was demonstrated and the tumor was
meticulously dissected from the nerve fascicles (b), and then completely
removed (c). The nodule was a  3 cm beige ball weighing  7 g.
10.1177_1756287219875578-fig1.jpg
PMC6767708_01_10.1177_1756287219875578-fig1.jpg
fig1-1756287219875578
Although painless, this median-nerve schwannoma was large enough ( 3 cm) to soon become a medical problem, and was thus readily resected without significant neural damage (Figure 1).
Microscopic characterization of the right-forearm schwannoma. (a) HES
stain, x100 magnification. (b) S100 protein immunostaining, x100
magnification.. HES, Hematoxylin-eosin-safran.
10.1177_1756287219875578-fig2.jpg
PMC6767708_01_10.1177_1756287219875578-fig2.jpg
fig2-1756287219875578
As shown in Figure 2a, the excised tumor consisted in spindle-shaped cells with poorly defined eosinophilic cytoplasm, without atypia, and with nuclear palisading. In addition, strong and uniform immunoreaction for S100 protein (polyclonal, Ventana, prediluted) was seen in all tumor cells (Figure 2b).
Preoperative MRI evaluation (a,b) and intraoperative view (c,d) of the
left-knee nodule. Two well-circumscribed lesions involving the common
fibular nerve and the tibial nerve, respectively, were identified (a,b).
While they both exhibited an heterogenous T2 hypersignal, they showed a
weak and strong gadolinium-mediated enhancement (not shown),
respectively. The common fibular nerve schwannoma was larger
(24 x 14 mm) than the tibial nerve one (15 x 9 mm) and was readily
enucleated without any neural damage (c,d). The common fibular nerve was
carefully handled and its upper part with its lateral sural cutaneous
branch was surgery free (c).. MRI, magnetic resonance imaging.
10.1177_1756287219875578-fig3.jpg
PMC6767708_02_10.1177_1756287219875578-fig3.jpg
fig3-1756287219875578
The second left-knee nodule is the third schwannoma identified so far (Figure 3a,b), thereby indicating that, even though it has not yet been resected and formally characterized, we are facing an age-related schwannomatosis or neurofibromatosis type 2 (NF2) case.
Microscopic characterization of the larger left-knee schwannoma (common
fibular nerve nodule). (a) HES stain, x50 magnification. (b) S100
protein immunostaining, x100 magnification.. HES, Hematoxylin-eosin-safran.
10.1177_1756287219875578-fig4.jpg
PMC6767708_01_10.1177_1756287219875578-fig4.jpg
fig4-1756287219875578
However, consistent with the MRI diagnosis, histologic and immunohistochemistry features were shown to be schwannoma-specific (Figure 4). Hematoxylin-eosin-safran (HES) stain disclosed alternating Antoni A and Antoni B patterns, hyalinized and thickened blood vessels, and cystic degenerative areas (Figure 4a). In addition, as in the aforementioned forearm nodule, strong and uniform immunoreaction was seen in all tumor cells for S100 protein (Figure 4b) but was absent for PSA (not shown).
PMC6767708_02
Preoperative MRI evaluation (a,b) and intraoperative view (c,d) of the
left-knee nodule. Two well-circumscribed lesions involving the common
fibular nerve and the tibial nerve, respectively, were identified (a,b).
While they both exhibited an heterogenous T2 hypersignal, they showed a
weak and strong gadolinium-mediated enhancement (not shown),
respectively. The common fibular nerve schwannoma was larger
(24 x 14 mm) than the tibial nerve one (15 x 9 mm) and was readily
enucleated without any neural damage (c,d). The common fibular nerve was
carefully handled and its upper part with its lateral sural cutaneous
branch was surgery free (c).. MRI, magnetic resonance imaging.
10.1177_1756287219875578-fig3.jpg
PMC6767708_02_10.1177_1756287219875578-fig3.jpg
fig3-1756287219875578
The second left-knee nodule is the third schwannoma identified so far (Figure 3a,b), thereby indicating that, even though it has not yet been resected and formally characterized, we are facing an age-related schwannomatosis or neurofibromatosis type 2 (NF2) case.