PMC6236481_01
(A) Hematoxylin and Eosin (H&E) stained section of the vertebral bone
showing a hypercellular marrow with diffuse sheets of blasts. (B) Blasts
showing strong positivity for CD3 immunohistochemical stain. (C) Blasts are
negative for CD20 immunohistochemical stain. (D) Blasts showing strong
positivity for CD1a immunohistochemical stain.
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Microscopic examination showed a hypercellular vertebral marrow (>95% cellularity) mostly consisting of diffuse sheets of blasts (Figure 1A); occasional surviving myeloid and erythroid elements were also seen. CD3 (Figure 1B) and negative for CD20 immunohistochemical stain (IHC) (Figure 1C). CD1a was expressed in more than 80% of the cells (Figure 1D) while CD8, CD34, and terminal deoxynucleotidyl transferase (TdT) IHCs were negative.
Section of thoracic spinal cord showing replacement of ventral horn cells by
sheets of macrophages and end-stage atrophy of the corresponding ventral
nerve root
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No surviving ventral horn cells were seen in the thoracic cord, and the corresponding ventral nerve roots showed end-stage atrophy with focal lymphocytic inflammation (Figure 2).
(A) Section of thoracic spinal cord showing complete replacement of gray
matter by macrophages and lymphocytes. (B) Section of thoracic spinal cord
showing complete loss of white matter in the dorsal column.
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The resorbing macrophages and lymphocytes also replaced the entire gray matter as well as the lateral and dorsal columns of the white matter (Figure 3A and B).
(A) A blood vessel showing prominent perivascular lymphocytic infiltrate. (B)
The perivascular lymphocytes are positive for CD3 immunohistochemical
stain.
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Most blood vessels in the spinal cord showed prominent perivascular lymphocytic infiltrates of CD3-positive T-lymphocytes (Figure 4).
CD68 immunohistochemical stain showing numerous macrophages in the thoracic
spinal cord.
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CD68 IHC showed a diffuse sheet of macrophages involving approximately 80% of the cord space (Figure 5).
Section of cervical spinal cord showing extensive necrosis of the gray matter
extending into the surrounding white matter.
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The cervical spinal cord showed extensive necrosis of the gray matter extending into the surrounding white matter (Figure 6).
Section of cervical spinal cord showing an area of cystic necrosis consisting
of resorbing macrophages, lymphocytes, and neuronal debris in the lateral
column.
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The white matter of the cervical cord showed focal necrotic areas of varying sizes consisting of resorbing macrophages, lymphocytes, and neuronal debris in the lateral and dorsal columns (Figure 7).
Luxol Fast Blue (LFB) stain showing subpial vacuolar degeneration and loss of
myelin in the dorsal column of cervical spinal cord.
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Luxol fast blue (LFB) stain showed loss of myelin in these degenerated areas (Figure 8).