Figure Legends
FIGURE 1: Postnatal ultrasound (A ) demonstrates a
heterogeneous fusiform solid mass (M) arising along the left back.
Calipers measure craniocaudal (1) and anteroposterior (2) dimensions.
Highly echogenic region subjacent to the mass denotes air at the pleural
surface (black arrows ) and a portion of the spinal column is
visible cranially (white arrowheads ). B Sagittal
fat-supressed T2-weighted MR image obtained at day 1 of life shows a
large encapsulated mass arising from the back (arrows ). Low
signal material within the mass (asterisk ) suggests a fibrous or
hemorrhagic component, whereas the remainder of the mass is composed of
higher signal tissue reflecting a larger cellular
component. C Preoperative clinical photograph shows a large
erythematous back mass with central skin ulceration (asterisk ),
the substance of which appears variably hemorrhagic and necrotic on
subsequent photograph of the resected specimen (D ).
FIGURE 2: Histological image of tumor at (A ) 40x
original magnification, (B, C ) 200x original magnification
showing tumor cells characterized by scanty cytoplasm, round nuclei with
neuroendocrine-type chromatin, and 1-2 small nucleoli. A subset of tumor
cells had increased clear cytoplasm (C ). Tumor cells diffusely
express BCOR based on IHC (D ; 200x original magnification).
Additional markers such as BRG1, CD56, CD99 (cytoplasmic, granular),
cyclin D1, INI1, pan-NTRK, TLE1, and vimentin showed strong diffuse
expression; diffuse moderate expression of BCL2, CD117, and nestin
(perinuclear dot pattern); focal expression of CD4 (perinuclear dot
pattern) and SATB2, and weak focal expression of EMA and MYOD1 were also
present. Pan cytokeratin (AE1/3), chromogranin, CD2, CD25, CD34, D2-40,
desmin, GFAP, HMB-45, myeloperoxidase, PHOX2B, PLAP, S100, SALL4, and
synaptophysin were negative. WGTA data showing somatic copy number
changes in all chromosomes. Red regions indicate copy gain: green
regions indicate copy loss (E ). Schema of the YWHAE-NUT2MB
fusion. B1:breakpoint 1. B2: breakpoint 2. Numbers in transcripts
indicate exons (F).