Metastatic involvement: imaging findings
Secondary lesions in the vertebrae have specific manifestations across various imaging modalities. Prostate cancer metastases are typically characterized by osteoblastic changes.
- Radiography: in the lateral projection, a moderate increase in the X-ray density of the affected vertebral body may be detected.
- CT (sagittal and axial planes): the classic pattern of an «ivory vertebra» (ivory vertebra) is formed. It occurs due to intense bone sclerosis. The process may spread to the pedicles, and accompanying osteoblastic foci are often found in adjacent vertebrae.
- MRI: on T2-weighted scans, the signal varies—lesions may appear dark (due to sclerosis) or have high intensity. A characteristic feature is intense contrast enhancement.
Primary spinal tumors
Primary neoplasms (Primary Vertebral Tumours) are relatively rare, accounting for about 10% of oncological lesions of the spinal column. They are diagnosed in patients of any age.
Based on growth pattern, they are classified as:
- Benign: hemangioma, osteoid osteoma, osteoblastoma, aneurysmal bone cyst, eosinophilic granuloma.
- Locally aggressive (locally aggressive): chordoma, giant cell tumor.
- Malignant: multiple myeloma, plasmacytoma, chondrosarcoma, osteosarcoma, Ewing's sarcoma.
The most frequent diagnoses in the general population are multiple myeloma and plasmacytoma. Chordoma leads among malignant processes of the cervical and sacral spine, while osteosarcoma ranks third in overall frequency.
Vertebral hemangioma
Hemangioma (Vertebral Haemangioma) is the most common benign spinal lesion. It is often detected incidentally, with multiple lesions found in 30% of patients. Most frequently (over 50%), the thoracic and lumbar spine are affected. The tumor is localized primarily within the vertebral body, but occasionally extends to posterior structures.
Imaging patterns:
- Radiography and CT (sagittal): «jail bar» sign (jail bar) — parallel vertical trabeculae against a background of osteopenic bone, or a honeycombed structure.
- CT (axial): «polka-dot» sign (polka-dot) — cross-sections of thickened bone trabeculae.
- MRI: high signal on T1- and T2-weighted images. Hyperintensity on T1 is related to the fibrofatty stroma. Upon fat suppression, T2 signal intensity drops. The lesion enhances with gadolinium.
If a hemangioma is aggressive, it exhibits low signal on T1, a large soft-tissue component (risk of spinal cord compression), and may mimic a malignant tumor (cortical destruction, lytic lesions).
Osteoid osteoma and osteoblastoma
These benign tumors share a similar histological structure (osteoblasts producing osteoid and woven bone). The main criterion for differential diagnosis is size.
| Sign | Osteoid osteoma | Osteoblastoma |
|---|---|---|
| Size | Less than 1.5 cm | More than 1.5 cm |
| Height | Self-limiting, well-defined margins | Malignant transformation is possible |
Osteoid osteoma typically presents in the second decade of life (mean age 17), more commonly in males. It is predominantly localized in the lumbar (60%) and cervical (30%) spine, affecting the posterior elements of the vertebra in half of the cases.
Briefly: answers to topical questions
What do osteoblastic spinal metastases look like on MRI?
On magnetic resonance imaging, osteoblastic spinal metastases appear as foci that may be dark (sclerotic) or demonstrate high signal on T2-weighted images.
Additional MRI features:
- Contrast enhancement — marked contrast enhancement is the rule.
- T1 signal alteration — a decrease in signal intensity on T1-weighted images (T1-WI) is characteristic.
- Specific sign — presence of a hyperintense «halo» (halo) around the lesion on fluid-sensitive sequences.
What imaging features are characteristic of osteolytic spinal metastases?
Osteolytic spinal metastases are characterized by bone destruction, often first identified on radiographs as destruction of the cortical layer of the vertebral pedicle (pedicle).
Main imaging features:
- Cancellous bone destruction — cross-sectional imaging modalities such as CT and MRI can demonstrate extensive destruction of the cancellous bone in the adjacent vertebral body.
- Soft-tissue component (soft-tissue mass) — may develop as the destructive process progresses.
- Periosteal reaction — may be observed, but is typically less pronounced than in primary malignant bone tumors.
What imaging features are characteristic of multiple myeloma of the spine?
A characteristic imaging feature of multiple myeloma of the spine is diffuse osteopenia, which can lead to multiple compression fractures.
Specific manifestations:
- Lytic lesions — well-demarcated «punched-out» defects or diffuse «punched-out lesions» (punched-out lesions).
- Pathological vertebral fractures — occur in approximately 50% of patients at a certain stage of the disease.
- MRI findings — sagittal T1-weighted MR images reveal heterogeneous signal intensity reduction from the bone marrow.
Class and exam questions
How does an osteoblastic metastasis look on CT?
It appears as an area of marked bone sclerosis, forming the «ivory vertebra» sign.
What distinguishes an aggressive vertebral hemangioma on MRI?
Aggressive hemangioma exhibits low signal on T1-WI and often features a prominent soft-tissue component capable of compressing the spinal cord.
What is the main imaging difference between osteoid osteoma and osteoblastoma?
The main distinguishing feature is the size of the lesion: osteoid osteoma measures less than 1.5 cm in diameter, whereas osteoblastoma exceeds this size.
What else to study on this topic
- Locally aggressive spinal tumors (chordoma, giant cell tumor)
- Malignant primary tumors: multiple myeloma and plasmacytoma
- Ewing's sarcoma and chondrosarcoma of the spine
- Transarterial embolization for hemangiomas
- Aneurysmal bone cyst and eosinophilic granuloma
Master the entire topic in the "Diagnostic Radiology" course
This is a summary. The course covers everything tested in classes and exams.
- Complete guide on «Spinal metastases» and 2,199 more pages on the subject
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 10 video lessons on the subject
Other topics in the "Spine" section
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.