PMC9276984_01
Osteoblastoma with multilevel ligamentum flavum ossification. (A) Sagittal CT and (B) T2-weighted and (C) fat-saturation post-contrast T1-weighted MR images show an expansile osseous lesion (arrow) centered at the right T9 lamina and pedicle with a central ring of enhancement. Note associated regional sclerosis in the T8-10 vertebral bodies (white arrowheads in A) and prominent multilevel ligamentum flavum ossification (black arrowheads in A). (D-F) Corresponding axial images show central lucency within the osseous lesion with heterogenous low T2 signal and enhancement (asterisk), as well as marked canal stenosis and cord compression (arrow in E). Note also enhancing right paravertebral soft tissue (arrowhead in E and F). Ligamentum flavum ossification and epidural lipomatosis also cause significant stenosis at T6-7, T7-8 and T8-9.
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F1
T9 with central lucency, enhancement and narrowing of the spinal canal at T9-10, as well as multifocal OLF most pronounced at T6-7 and to a lesser degree at T7-8 and T8-9 (Figure 1). Together, these findings were suggestive of osteoblastoma with associated OLF and reactive bone and soft tissue inflammation, often described as the osteoblastoma flare phenomenon.
Surgical resection and decompression. (A) Sagittal T2-weighted MRI of the thoracic spine after initial resection and decompression, prior to stabilization. (B) Three-month follow up sagittal T2-weighted MRI after further decompression and stabilization, without residual spinal stenosis.
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F2
At his 3-month follow up visit, the patient had complete resolution of his neurological symptoms with stable imaging findings (Figure 2).
Histopathological characteristics assessed on surgical resection. (A) The section shows the reactive, benign chondro-osseous tissue and adjacent fibrous tissue that comprised the ossification of the ligamentum flavum specimen. Scale bar, 250 microm. (B,C) Representative sections show the anastomosing trabeculae of woven bone with loose fibrovascular stroma with focal hemorrhage and congested blood vessels, consistent with osteoblastoma. Scale bar, 250 microm. (D) Area of tumor with prominent osteoblastic rimming. Scale bar, 125 microm.
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F3
Loose fibrovascular stroma with focal hemorrhage and vascular congestion was seen between the trabeculae, consistent with the diagnosis of osteoblastoma (Figure 3).