Paraplegia Caused by Multifocal Osteosarcoma With Spinal Lesions

CASE PRESENTATION

A 55-year-old man initially presented to a nearby hospital with low back pain of more than 1 month duration. Multiple osteosclerotic lesions were observed in the spine and pelvis. Biopsy of the iliac lesion was performed, and he was diagnosed with osteosarcoma and referred to our institute. He reported no fever but complained of general fatigue. Laboratory test results were normal, except for a markedly elevated alkaline phosphatase (ALP) level of 36,416 U/L (normal range, 115–359 U/L). The inflammatory marker C-reactive protein value was negative (<0.1 mg/dL). His leukocyte count was normal at 4370/mm³ (neutrophils, 64.3%; lymphocytes, 22.4%; monocytes, 8.2%; eosinophils, 3.0%; and basophils, 2.1%).

Plain radiographs showed diffuse osteosclerotic lesions in the spine and pelvis (Figure 1A). Magnetic resonance imaging (MRI) demonstrated vertebral and pelvic lesions with low-signal intensity on T1- and T2-weighted images (Figure 1B). Bone scintigraphy demonstrated systemic bone lesions, primarily in the trunk (Figure 1C). Extraosseous ossified lesions were also observed in soft tissue of the mediastinum, retroperitoneum, and mesentery on computed tomography (CT) (Figure 1D). The patient received chemotherapy for palliation. The chemotherapeutic regimen consisted of 1.5 g/m² ifosfamide per day for 3 days, carboplatin 300 mg/m² per day for 3 days, and 100 mg/m² etoposide per day for 3 days. Laboratory tests showed that his ALP level had decreased to 17,833 U/L after 6 treatment courses and that his ALP levels had been controlled at <25,000 U/L throughout the 6 months of chemotherapy. After 6 courses of chemotherapy, he began experiencing back pain and gait disturbance, and his knee gave way. Due to decreased daily activity and onset of general fatigue, chemotherapy was discontinued, and his ALP level increased to 49,943 U/L 1.5 months later.

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Figure 1

A 55-year-old man with multicentric osteosarcoma. Plain radiography shows multifocal osteosclerotic lesions in the pelvis and spine (A). Magnetic resonance imaging shows multiple vertebral and pelvic lesions with low-signal intensity on T2-weighted (B-top, middle) and T1-weighted (B-bottom) images. Whole-body bone imaging using technetium-99m shows uptake primarily in the bone of the trunk (C). A lesion is observed in the lung (yellow arrow), but it is relatively small in size (C-top). Extraosseous ossified lesions are observed in the mediastinum (top), retroperitoneum (middle), and mesentery (bottom) (D) (orange arrows).

On physical examination, his muscles had slightly weakened. However, deep patellar tendon reflexes and achilleas tendon reflexes were elicited. CT and MRI showed an increase in size of the ossified lesion in the spine, as well as compression of the spinal cord at the level of T9-10 (Figure 2A,B), so (Figure 2)decompression and posterior spinal stabilization of T8-12 were performed (Figure 2C). The resected vertebral laminae were confirmed to harbor osteosarcoma (Figure 2D). After surgery, the patient experienced improvement in gait. One month after surgery, he noticed muscle weakness of the right upper extremity and right thigh pain. His right extremity weakness was judged to be fair and he was able to move the extremity against gravity (Manual Muscle Testing Grading System, grade 3). In contrast, no palpable contraction was observed in either of the lower extremities (Manual Muscle Testing Grading System, grade 0), indicating paraplegia. He developed bladder and rectal disturbances. CT showed narrowing of the spinal canal and spinal cord compression at T6 and T7, which were above the fixed vertebrae (Figure 2D). The weakness of the right upper extremity was diagnosed due to radiculopathy in the cervical spine. The paraplegia and right upper extremity caused a decreased performance state. Ossified lesions in the bone and soft tissue continued to increase in size (Figure 2D,E). Eleven months after the first visit to our hospital, the patient died of multiple organ failure.

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Figure 2

A 55-year-old man with multicentric osteosarcoma. In the osteosclerotic spine, the spinal canal is narrowed at T10-11. An axial view at T10 shows that this narrowing is due to an ossified lesion (A). Magnetic resonance imaging shows compression of the spinal cord (yellow arrow) on a T2-weighted image (B). Fixation and decompression of T8–12 was performed (C). Histologic analysis of the resected laminae shows an osteoid tumor with atypical cells among trabecular bone (D-top). Two months after surgery, the spinal canal is narrowed at T7 (D-bottom). Extraosseous lesions are indicated with orange arrows (D and E). The ossified lesion in the pelvis is increased in size (E).