Intermittent low back pain of two years duration. No history of trauma or other chronic disease.
The patient was admitted because of intermittent low back pain of two years duration. No history of trauma or other chronic disease was noted.
On physical examination local tenderness over the lower thoracic spine was found. Neurological and laboratory examinations, the latter including alkaline phosphatase activity, were normal. Conventional radiography, whole body scintigraphy, CT scan, MRI of the thoracoclumbar spine, and bone biopsy were performed.
On conventional radiograph of the thoraco-lumbar spine (AP-view) (fig. 1), the Th 12 vertebra appears hyperdense and moderately enlarged. Bone scintigraphy of the thoraco-lumbar spine (AP-view) (fig. 2) shows highly increased uptake at the vertebral body of Th12.
CT scan at the level of Th12 (fig. 3) demonstrates focal radiodense areas ("cotton wool" aspect) with interspersed lucent areas mainly affecting the vertebral body.
MR of the thoraco-lumbar spine (fig. 4) included a sagittal T1-weighted image (A) showing low signal intensity of the Th12 vertebral body, a sagittal T2-weighted image (B) demonstrating a moderately decreased signal intensity of Th12, and a Gd-enhanced sagittal T1-weighted image (C) displaying a rim of peripheral enhancement ("picture frame") at the level of Th12. Enhancement of some vertical trabeculae within this vertebral body is also noted.
The radiological and clinical findings were diagnostic of Paget disease affecting a single vertebra. Bone biopsy confirmed this diagnosis.
Monostotic Paget’s disease is uncommon (10 to 20%). The radiographic appearance during the course of the disease is explained by the underlying pathologic processes. The initial phase of increased osteoclastic activity resulting in bone resorption is not commonly seen radiographically. During the second phase a mosaic pattern is observed, which reflects the increased formation of abnormally coarsened trabeculae, following the first episod of increased bone resorption. The last phase, during which osteoclastic activity declines and osteoblastic activity proceeds, results in disorganized new bone formation of increased density, replacing the previous lytic areas. This phase represents the sclerotic phase. All three types of lesions may be found in the affected vertebra, which appears characteristically enlarged.
The MR appearance in Paget of the spine is variable. Focal or diffuse low signal intensity on short TR/TE and long TR/TE images are due to the presence of dense bone and fibrous tissue. However, in some patients different patterns are encountered, such as low signal intensity on short TR/TE and high signal intensity on long TR/TE images or high signal intensity on both T1 and T2 sequences. Vertebral enlargement is seldom seen in osteoporotic or malignant disease. Pathologic fractures are the commonest complication of Paget’s disease and may cause spinal nerve compression.
Secondary malignant degeneration to osteogenic sarcoma and to a lesser extent fibrosarcoma, chondrosarcoma, and malignant fibrous histiocytoma may occur.
Paget disease
From the provided X-ray, radionuclide bone scan, and MRI images, the following can be observed:
1. The lumbar vertebral body (especially a single vertebra) shows mild enlargement or deformation in shape, with uneven density. Local sclerotic areas and partial lytic changes can be seen, presenting “puzzle-like” or “patchy” changes.
2. The radionuclide bone scan shows high radioactive uptake in this vertebra, suggesting hyperactive metabolic activity.
3. On MRI, the vertebral body signal is heterogeneous: On T1-weighted sequences, some areas show decreased or slightly increased signal; on T2-weighted sequences, high signal, low signal, or mixed signals coexist, consistent with uneven bone tissue and fibrous tissue proliferation as well as new bone formation.
4. No obvious vertebral collapse or significant soft tissue mass is observed, nor is there a clear sign of spinal cord or nerve root compression. However, the risk of pathological fracture due to long-standing lesions should be noted.
The vertebra shows enlargement, disorganized bony structure, and uneven density, commonly seen in middle-aged and elderly patients. Imaging often reveals “puzzle-like” or polyphasic changes, matching the classic features of Paget’s disease. Bone scans show high uptake, indicating high metabolic activity. The relatively slow progression of symptoms aligns with its chronic course.
It can also present with lytic or sclerotic changes, but vertebral enlargement is uncommon. Most metastatic tumors involve obvious bone destruction and progressively worsening pain. Additionally, if malignancy metastasizes, there would typically be noticeable soft tissue masses or signs of metastases elsewhere. Such findings are not prominent in the current imaging.
Osteoporosis can lead to thinner trabeculae and vertebral collapse, but usually does not cause vertebral enlargement. Moreover, the “puzzle-like” pattern and local sclerosis are absent, which does not match the characteristics in this case.
Considering the patient’s age, the chronic course of low back pain, and the X-ray/bone scan/MRI features, along with the polyphasic changes and enlargement of the vertebra, the most likely diagnosis is:
Monostotic Paget’s Disease of the Vertebra.
Although Paget’s disease often presents as multiple lesions, it can also appear as a focal (monostotic) lesion, accounting for around 10-20% of cases. If further confirmation is required, serum alkaline phosphatase testing, bone turnover marker evaluation, or biopsy can be considered to rule out malignant transformation.
1. Treatment Strategy:
(1) Medication: Bisphosphonates (e.g., alendronate) can be considered to control abnormal bone remodeling, and calcium and vitamin D supplementation may be employed to enhance bone health.
(2) Follow-up Observation: If the disease progresses slowly or symptoms are mild, regular imaging follow-up and monitoring of bone metabolic indicators can help prevent pathological fractures.
(3) Surgical Intervention: For cases with significant deformity, nerve compression, or a high risk of pathological fracture, decompression or internal fixation surgery may be considered.
2. Rehabilitation and Exercise Prescription:
Once the affected vertebra is confirmed to be stable, a gradual rehabilitation program and exercise prescription can promote bone health and restore lumbar and back muscle function. Based on the FITT-VP principle, the recommendations are as follows:
(1) Frequency: 3-5 times per week.
(2) Intensity: Begin with low to moderate intensity (around 40-60% of the maximum heart rate), and gradually increase according to individual tolerance.
(3) Time: Start with 20-30 minutes per session and gradually extend to 30-45 minutes, depending on tolerance and recovery.
(4) Type:
Disclaimer: This report is a reference analysis based on the currently provided information and cannot replace an in-person consultation or professional medical advice. If you have any questions or symptoms worsen, please seek prompt medical evaluation by a qualified professional.
Paget disease
