A rare case of spinal myeloid sarcoma

Abstract

Background: Myeloid sarcoma (MS), a rare extramedullary tumor composed of myeloid blast cells, is classified by the World Health Organization as a subtype of acute myeloid leukemia (AML). Isolated, primary, or nonleukemic MS has an incidence of 2/1,000,000 adults and constitutes only 0.7% of all AML cases. MS presentations vary widely, with spinal involvement being rare.

Case description: A-year-old male presented with interscapular pain radiating to the right upper arm/neck but was neurologically intact. Once diagnosed with isolated spinal MS, he underwent a surgical decompression followed by local irradiation, systemic chemotherapy, and bone marrow transplantation. Eight months postoperatively, however, he experienced a graft-versus-host rejection and required additional therapies.

Conclusion: Establishing the diagnosis of MS is challenging and typically requires histological confirmation (i.e., the presence of myeloblasts and granulocytic cells). However, optimal treatment strategies remain elusive; despite radiation, chemotherapy, bone marrow transplant/other local therapies, the overall long-term prognosis for MS remains poor.

Keywords: Compression fracture; Myeloid sarcoma; Polycythemia vera; Spinal tumor; Thoracic spine.

Figure 1:

(a) Sagittal T2-weighted image of the upper thoracic spine, showing an impression fracture of the Th3 vertebral body, with pathological signal alteration, bulging into the spinal canal, with slight compression of the dural sac. There is no myelomalacia. (b) Axial T2-weighted image of the affected Th3 vertebra. (c) Fluorodeoxyglucose-positron emission tomography/computed tomography scan in the sagittal plane shows increased tracer captation of the Th3 vertebral body; there are no suspicious lesions elsewhere.

Figure 2:

(a and b) Expression of CD45 and CD34 in tumor cells. (c) ×200 magnification of a monomorphic of immature myeloid cells with pale cytoplasm and vesicular nuclei. (d) Low-power view (×50 magnification) of the diffuse growing tumor, next to fragments of the ligamentum flavum. (HE=Haematoxylin and eosin stain)

Figure 3:

Postoperative plain radiograph imaging in the (a) sagittal and (b) coronal plane.