PMC9260570_01
Axial (a) and coronal (b) fused PET-CT images show a large mass (arrows) in the left
hemithorax with foci of increased metabolic activity. No metastatic disease is
seen.
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PET-CT was subsequently performed. (Figure 1) A CT-guided biopsy was performed. Pathologic analysis showed an undifferentiated neuroectodermal sarcoma which stained positive for CD99 and FLI1. (Figure 2) The biopsy specimen was sent for molecular gene rearrangement studies and an EWSR1 rearrangement was detected.
Sections show small round cell tumor composed of undifferentiated round cells. Tumor
cells are positive for CD99 and Fli-1 immunostains, focally positive for WT1 and
negative for CK5/6, p63, TTF-1, chromogranin, synaptophysin, Melan-A, CD45, CD3, CD20,
CD34, S-100, MPO and desmin. EWSR1 gene rearrangement detected at NeoDenomics Lab.
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PET-CT was subsequently performed. (Figure 1) A CT-guided biopsy was performed. Pathologic analysis showed an undifferentiated neuroectodermal sarcoma which stained positive for CD99 and FLI1. (Figure 2) The biopsy specimen was sent for molecular gene rearrangement studies and an EWSR1 rearrangement was detected.
Coronal maximum intensity projection (MIP) image of PET-CT, shows new metabolic
activity (long white arrow) in right paraesophageal lymph node, a metastatic focus in
the right proximal femur (arrowhead), and another metastatic focus in the left
acetabulum (squiggly arrow). Note increased metabolic activity in a paraaortic nodule
lymph node (black arrow) in the epigastrium, felt to be reactive enlarged lymph
node.
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August 2019. A re-staging PET/CT showed significant improvement with some scarring in the area, but with increased metabolic activity in the acetabulum, a para-esophageal lymph node, an enlarged paraaortic nodule, and a hypermetabolic focus in the right proximal femur concerning new osseous metastasis. (Figure 3) In December 2019, she underwent palliative radiation to the right femur.
Coronal maximum intensity projection image from the most recent PET-CT shows near
complete resolution of metabolic hyperactivity in the paraesophageal lymph node. Post
radiation changes are seen in the right upper thigh. The activity in the left
acetabulum has decreased with central area of absent activity suggesting central
necrosis. The activity in the presumed reactive lymph node in the epigastric region
has also returned to normal.
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Restaging PET-CT scans have shown improvement with no recurrence or new metastatic disease (Figure 4).