A case report on non-metastatic Ewing sarcoma of the lumbar spine in a young patient

Abstract

Background: Ewing sarcoma (ES), the second most common malignant bone tumor after osteosarcoma in the second decade, occurs in 0.9% of cases as the primary non-sacral form.

Case: A 20-years-old male presented with acute paraparesis of bilateral lower limb and numbness following initial back pain for the last 6 months. Magnetic resonance imaging (MRI) of the lumbar spine revealed a 4 cm enhancing soft tissue mass at the L4/L5 vertebra extending into the spinal canal with compression of the thecal sac. The computed tomography (CT) of the chest, abdomen, and pelvis revealed aggressive lytic lesions in the L4 spinous process with soft tissue extension into the spinal canal with no other site of distant metastasis. He was treated with IV steroids (Injection dexamethasone 10 mg IV followed by 4 mg tablet dexamethasone q6h; subsequently tapered off). A core needle biopsy showed a small, round blue cell neoplasm, (suggestive of a primitive neuroectodermal) stained positive for CD99 and vimentin stain. The diagnosis of ES lumbar spine was made which was treated with surgical resection with an appropriate margin measuring 8 × 4.5 × 2.5 cm with decompression and L4/5 laminectomies, which had a negative margin in the surgical pathology report. Concomitant local radiotherapy and chemotherapy [cycles of vincristine 2 mg/m² , adriamycin/doxorubicin 75 mg/m² , cyclophosphamide 1200 mg/m² (VDC) with mesna rescue alternating with cycles of ifosfamide 1800 mg/m² and etoposide 100 mg/m² (IE)] was started. The motor strength was regained gradually with preserved spine biomechanics and oncological control with no recurrence in 2-year follow-ups.

Conclusions: The presentation of lumbar ES can vary from local pain and swelling to acute paraparesis. Timely diagnosis and treatment with multimodal therapy, namely, steroids for acute spinal cord compression and surgery with chemoradiotherapy for ES can improve spinal biomechanics and oncological control.

Keywords: Ewing sarcoma; case report; laminectomy; lumbar spine; spinal neoplasm.

FIGURE 1

MRI of the lumbar spine showing enhancing soft tissue mass at the L4/5 vertebra extending into the spinal canal with compression of the thecal sac (red arrow).

FIGURE 2

Tissue biopsy histology showing poorly differentiated small, round blue cell neoplasm suggestive of ES (40X)

FIGURE 3

A. Immunohistochemistry of core needle biopsy; positive for CD99 stain (40X). B. Immunohistochemistry of core needle biopsy; positive for vimentin (40X)

FIGURE 4

The PET CT scan showed post‐procedure changes with dorsal seroma without focal uptake

FIGURE 5

Postoperative MRI lumbar spine showing L3, L4, and L5 vertebral body fusion; L3 laminotomy; L4/L5 laminectomies; without any enhancement, foraminal narrowing, or disc herniation or alignment changes