JHS 49.6 - June 2024 - 759

Hems et al.
759
neural crest origin able to produce various types of
collagen, myelin and to follow several metaplastic/
divergent paths of differentiation, which is reflected
in the morphologic heterogeneity of peripheral nerve
neoplasms (Jessen and Mirsky, 2005). Peripheral
nerve tumours show several peculiar features, such
as frequent association with genetic disorders, particularly
neurofibromatosis type 1 (NF1) (Antonescu
et al., 2013; Jessen and Mirsky, 2005). The pathology
of the solid peripheral nerve tumours is reviewed
below, but cystic lesions, including intraneural ganglions,
can occur (Panwar et al., 2017).
Schwannoma
Schwannoma is a benign tumour composed of
Schwann cells that arises frequently in the skin
and subcutaneous tissue of the head and neck
region and the extremities, particularly along the
flexor surface (World Health Organization [WHO],
2020). Schwannomas are usually solitary and sporadic,
may affect all ages (peak incidence in 4th-6th
decades), often present as slow-growing asymptomatic
lesions <10 cm, but can also be painful. Fewer
than 50% are attached to a nerve that is often small
with uninvolved nerve fascicles draped over the
tumour capsule (WHO, 2020). Inactivating mutations
of the neurofibromatosis type 2 (NF2) gene are found
in approximately 50%-75% (Lassaletta et al., 2013;
Oh et al., 2015) of sporadic cases, while in schwannomatosis
a three- or four-hit oncogenic mechanism
is involved, for example, a germline mutation (in DNA
in sperm or egg cells) of SMARCB1 or LZTR1 followed
by a somatic mutation (occurring after conception
in cells other than egg and sperm) of NF2 on the
same chromosome 22 and a deletion of the entire
other chromosome 22 (Kehrer-Sawatzki et al., 2017).
Upon microscopic examination (Figure 1),
schwannomas present as an encapsulated tumour
with different morphological features: cellular
areas, called 'Antoni A', containing spindle cells
with eosinophilic cytoplasm, indefinite cell borders
and tapering nuclei and occasional nuclear palisading
(Verocay bodies), alternate with more hypocellular
areas called 'Antoni B', containing a network of
tumour cell processes, histiocytes and blood vessels
with hyalinized walls (Antonescu et al., 2013; WHO,
2020). Several morphologic subtypes are described:
'ancient' with isolated atypical/bizarre nuclei, cellular,
plexiform, epithelioid and others (Antonescu
et al., 2013; WHO, 2020). All subtypes of schwannoma
are strongly reactive to S100 protein and SOX10
immunostainings (Karamchandani et al., 2012).
They are benign and rarely recur after total resection.
The presence of focal malignant changes has
been reported in very few cases of otherwise
Figure 1. Histological sections of a schwannoma. (a) Nuclear palisades (Verocay bodies) (original magnification 10);
(b) Schwann cells with scattered bizarre nuclei ( " ancient " features) (original magnification 20); (c) S100 staining and (d)
SX10 staining.

JHS 49.6 - June 2024

Table of Contents for the Digital Edition of JHS 49.6 - June 2024

Contents
JHS 49.6 - June 2024 - Cover1
JHS 49.6 - June 2024 - Cover2
JHS 49.6 - June 2024 - 660
JHS 49.6 - June 2024 - 661
JHS 49.6 - June 2024 - Contents
JHS 49.6 - June 2024 - 663
JHS 49.6 - June 2024 - 664
JHS 49.6 - June 2024 - 665
JHS 49.6 - June 2024 - 666
JHS 49.6 - June 2024 - 667
JHS 49.6 - June 2024 - 668
JHS 49.6 - June 2024 - 669
JHS 49.6 - June 2024 - 670
JHS 49.6 - June 2024 - 671
JHS 49.6 - June 2024 - 672
JHS 49.6 - June 2024 - 673
JHS 49.6 - June 2024 - 674
JHS 49.6 - June 2024 - 675
JHS 49.6 - June 2024 - 676
JHS 49.6 - June 2024 - 677
JHS 49.6 - June 2024 - 678
JHS 49.6 - June 2024 - 679
JHS 49.6 - June 2024 - 680
JHS 49.6 - June 2024 - 681
JHS 49.6 - June 2024 - 682
JHS 49.6 - June 2024 - 683
JHS 49.6 - June 2024 - 684
JHS 49.6 - June 2024 - 685
JHS 49.6 - June 2024 - 686
JHS 49.6 - June 2024 - 687
JHS 49.6 - June 2024 - 688
JHS 49.6 - June 2024 - 689
JHS 49.6 - June 2024 - 690
JHS 49.6 - June 2024 - 691
JHS 49.6 - June 2024 - 692
JHS 49.6 - June 2024 - 693
JHS 49.6 - June 2024 - 694
JHS 49.6 - June 2024 - 695
JHS 49.6 - June 2024 - 696
JHS 49.6 - June 2024 - 697
JHS 49.6 - June 2024 - 698
JHS 49.6 - June 2024 - 699
JHS 49.6 - June 2024 - 700
JHS 49.6 - June 2024 - 701
JHS 49.6 - June 2024 - 702
JHS 49.6 - June 2024 - 703
JHS 49.6 - June 2024 - 704
JHS 49.6 - June 2024 - 705
JHS 49.6 - June 2024 - 706
JHS 49.6 - June 2024 - 707
JHS 49.6 - June 2024 - 708
JHS 49.6 - June 2024 - 709
JHS 49.6 - June 2024 - 710
JHS 49.6 - June 2024 - 711
JHS 49.6 - June 2024 - 712
JHS 49.6 - June 2024 - 713
JHS 49.6 - June 2024 - 714
JHS 49.6 - June 2024 - 715
JHS 49.6 - June 2024 - 716
JHS 49.6 - June 2024 - 717
JHS 49.6 - June 2024 - 718
JHS 49.6 - June 2024 - 719
JHS 49.6 - June 2024 - 720
JHS 49.6 - June 2024 - 721
JHS 49.6 - June 2024 - 722
JHS 49.6 - June 2024 - 723
JHS 49.6 - June 2024 - 724
JHS 49.6 - June 2024 - 725
JHS 49.6 - June 2024 - 726
JHS 49.6 - June 2024 - 727
JHS 49.6 - June 2024 - 728
JHS 49.6 - June 2024 - 729
JHS 49.6 - June 2024 - 730
JHS 49.6 - June 2024 - 731
JHS 49.6 - June 2024 - 732
JHS 49.6 - June 2024 - 733
JHS 49.6 - June 2024 - 734
JHS 49.6 - June 2024 - 735
JHS 49.6 - June 2024 - 736
JHS 49.6 - June 2024 - 737
JHS 49.6 - June 2024 - 738
JHS 49.6 - June 2024 - 739
JHS 49.6 - June 2024 - 740
JHS 49.6 - June 2024 - 741
JHS 49.6 - June 2024 - 742
JHS 49.6 - June 2024 - 743
JHS 49.6 - June 2024 - 744
JHS 49.6 - June 2024 - 745
JHS 49.6 - June 2024 - 746
JHS 49.6 - June 2024 - 747
JHS 49.6 - June 2024 - 748
JHS 49.6 - June 2024 - 749
JHS 49.6 - June 2024 - 750
JHS 49.6 - June 2024 - 751
JHS 49.6 - June 2024 - 752
JHS 49.6 - June 2024 - 753
JHS 49.6 - June 2024 - 754
JHS 49.6 - June 2024 - 755
JHS 49.6 - June 2024 - 756
JHS 49.6 - June 2024 - 757
JHS 49.6 - June 2024 - 758
JHS 49.6 - June 2024 - 759
JHS 49.6 - June 2024 - 760
JHS 49.6 - June 2024 - 761
JHS 49.6 - June 2024 - 762
JHS 49.6 - June 2024 - 763
JHS 49.6 - June 2024 - 764
JHS 49.6 - June 2024 - 765
JHS 49.6 - June 2024 - 766
JHS 49.6 - June 2024 - 767
JHS 49.6 - June 2024 - 768
JHS 49.6 - June 2024 - 769
JHS 49.6 - June 2024 - 770
JHS 49.6 - June 2024 - 771
JHS 49.6 - June 2024 - 772
JHS 49.6 - June 2024 - 773
JHS 49.6 - June 2024 - 774
JHS 49.6 - June 2024 - 775
JHS 49.6 - June 2024 - 776
JHS 49.6 - June 2024 - 777
JHS 49.6 - June 2024 - 778
JHS 49.6 - June 2024 - 779
JHS 49.6 - June 2024 - 780
JHS 49.6 - June 2024 - 781
JHS 49.6 - June 2024 - 782
JHS 49.6 - June 2024 - 783
JHS 49.6 - June 2024 - 784
JHS 49.6 - June 2024 - 785
JHS 49.6 - June 2024 - 786
JHS 49.6 - June 2024 - 787
JHS 49.6 - June 2024 - 788
JHS 49.6 - June 2024 - 789
JHS 49.6 - June 2024 - 790
JHS 49.6 - June 2024 - 791
JHS 49.6 - June 2024 - 792
JHS 49.6 - June 2024 - 793
JHS 49.6 - June 2024 - 794
JHS 49.6 - June 2024 - 795
JHS 49.6 - June 2024 - 796
JHS 49.6 - June 2024 - 797
JHS 49.6 - June 2024 - 798
JHS 49.6 - June 2024 - 799
JHS 49.6 - June 2024 - 800
JHS 49.6 - June 2024 - 801
JHS 49.6 - June 2024 - 802
JHS 49.6 - June 2024 - 803
JHS 49.6 - June 2024 - 804
JHS 49.6 - June 2024 - 805
JHS 49.6 - June 2024 - 806
JHS 49.6 - June 2024 - 807
JHS 49.6 - June 2024 - 808
JHS 49.6 - June 2024 - 809
JHS 49.6 - June 2024 - 810
JHS 49.6 - June 2024 - 811
JHS 49.6 - June 2024 - 812
JHS 49.6 - June 2024 - 813
JHS 49.6 - June 2024 - 814
JHS 49.6 - June 2024 - 815
JHS 49.6 - June 2024 - 816
JHS 49.6 - June 2024 - 817
JHS 49.6 - June 2024 - 818
JHS 49.6 - June 2024 - 819
JHS 49.6 - June 2024 - 820
JHS 49.6 - June 2024 - 821
JHS 49.6 - June 2024 - 822
JHS 49.6 - June 2024 - 823
JHS 49.6 - June 2024 - 824
JHS 49.6 - June 2024 - 825
JHS 49.6 - June 2024 - 826
JHS 49.6 - June 2024 - 827
JHS 49.6 - June 2024 - 828
JHS 49.6 - June 2024 - Cover3
JHS 49.6 - June 2024 - Cover4
https://www.nxtbookmedia.com