case_images: PMC9677177_01
case_images: Lumbar CT scan in parenchymal window (a) and bone window (b and c) showing a lesional process centered on the epidural space extended from D11 to L2, centered at the level of D11-D12 slightly enhanced after injection of contrast medium, infiltrating the vertebral bodies and the conjugation holes opposite and the adjacent soft parts.
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case_images: A CT scan of the spine was ordered and showed a lesional process in the epidural space extending from D11 to L2, centered at D12-L1, infiltrating the vertebral bodies and the holes of conjugation (Figure 1).
case_images: Sagittal and axial sections of a dorsolumbar MRI showing a lesional process centered on the vertebral body of L1 in T1 hyposignal, heterogeneous T2 signal, discretely and heterogeneously enhanced after injection of Gadolinium, without bulging of the posterior wall or involvement of the posterior arch, associated with epiduritis, endocanal extension and spinal cord compression.
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case_images: The MRI complement showed the presence of a lesion process centered on the vertebral body of L1 in T1 hyposignal, T2 hyposignal, heterogeneously enhanced after injection of gadolinium respecting the posterior arch, without bulging of the posterior wall with epiduritis, endocanal extension and spinal cord compression (Figure 2).
case_images: (a): Round cell tumor proliferation with pseudorosette images; HE staining at x40 magnification. (b): Immunostaining with anti CD99 antibody: diffuse membrane staining.
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case_images: Indeed, the histopathology showed a malignant tumor proliferation made of round cells of more or less lobulated architecture with pseudorosettes in some places (Figure 3a). Immunohistochemistry showed diffuse positive membrane staining of tumor cells with the anti-CD99 antibody (Figure 3b) with an estimated high proliferation index of 40%.
case_images: Axial (a and b) and coronal (c) sections of a chest CT scan in the parenchymal window showing multiple diffuse bilateral pulmonary nodules with random distribution realizing the balloon-release appearance related to pulmonary metastases.
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case_images: Actin smooth muscle; EMA; PS100; and synaptophysin antibodies remained negative. A thoracic-abdominal-pelvic CT scan was performed as part of the extension workup and showed multiple diffuse bilateral pulmonary nodules involving both lung fields with a random distribution realizing a "Release of balloons" sign indicating secondary locations (metastases) (Figure 4), the evolution was marked by a good initial improvement of motor weakness.