A 23-year-old man presented with an 18 months history of progressive right upper extremity pain and ipsilateral muscle weakness. Patient’s history revealed that the pain was initially nocturnal and was gradually increasing in severity. Orthopaedic examination and electromyography suggested the diagnosis of a brachial plexus radiculopathy.
Initial CT examination performed elsewhere 18 months ago was interpreted as normal (Fig.1) and the patient was treated with oral NSAID for muscle strain injury. Three months later, an MRI exam was requested, due to deterioration of symptoms. The MRI was performed elsewhere and was interpreted as being “within normal limits” (Fig.2a,b). Eight months after onset of symptoms while no symptom improvement occurred, a head MRI was performed to investigate possible CNS origin of the symptomatology. The axial FLAIR images demonstrated scattered focal subcortical and deep white matter lesions, indicative of multiple sclerosis (Fig.3). The subsequent visual, somatosensory and motor evoked potentials as well as CSF analysis were negative for a demyelinating disease and the patient was referred to a psychiatric clinic for investigation of a possible underlying depression. After 6 months of unsuccessful antidepressant therapy and intolerable pain, the patient was scheduled for a new MRI exam of the brachial plexus. A mass projecting into the right foramen C6-7 exhibiting low signal intensity on T1-w and T2-w images and marked enhancement of the lesion and the surrounding soft tissues on contrast-enhanced fat saturated T1-w images was depicted (Fig. 4). An additional CT study (Fig. 5) showed an expansile lytic lesion in the facet joints with central osteoid formation and discontinuity of the rim. Based on the series of imaging studies, the diagnosis of osteoblastoma was suggested which was established after complete tumor resection.
Osteoblastoma is a rare bone tumor with a reported incidence of 1% of all primary bone tumors and with a male-female ratio of 2:1. Peak age of presentation is in the 2nd -3rd decade. Spinal involvement has been estimated to be between 32% and 46% with equal frequency in the cervical, thoracic, and lumbar vertebrae. The tumor has a predilection for the neural arch with further invasion of the vertebral body. Clinical manifestations vary from nearly asymptomatic cases to localized back pain or more advanced symptomatology due to tumor’s local progression and compression of adjacent neural elements. Plain radiographs can be diagnostic provided that the lesion has increased size at presentation. CT provides with additional information regarding the matrix of the small sized lesions. Both CT and MRI are superior for local staging and for biopsy or surgical planning. The radiologic features of osteoblastoma in CT imaging are an osseous expansile lytic lesion with a diameter usually greater than 2 cm, evidence of osteoid matrix production and possible soft tissue components. MRI is less specific for diagnosis and is characterized by overestimation of the tumor’s actual size due to associated adjacent soft-tissue inflammatory changes (“flare phenomenon”). Depending on the level of matrix mineralization, a low-to-intermediate signal intensity on T1-w and a low-to-high signal intensity on T2-w MR images is observed. Intense contrast enhancement is noted following the injection of gadolinium-based contrast agents. Bone scintigraphy demonstrates marked radionuclide uptake.
The main purpose of this case report is to emphasize the similarity in imaging as well as clinical presentation between osteoblastoma and osteoid osteoma at presentation. Histologically both tumors are similar, containing osteoblasts that produce osteoid and woven bone. The differentiation is mainly based on tumor size. In our case the tumor could be interpreted as osteoid osteoma in the initial CT scan. The small high signal intensity lesions within the brain parenchyma, were considered to be incidental findings (UBOs) and definitely irrelevant to osteoblastoma. One year following the operation, the routine clinical follow up did not reveal any CNS abnormalities. The difference in appearance of the lesion regarding both the size and the central nidus alterations could be explained on the grounds of an enlarging lesion with bone resorption and un-mineralized matrix formation.
Osteoblastoma
Based on the provided CT and MRI images, as well as the patient’s clinical symptoms, the lesion is primarily located in the posterior elements of the cervical vertebrae (mainly on the right side). It appears as a relatively large lytic lesion with mild expansile changes. CT shows significant bone destruction with a sclerotic margin, and partial calcification or osseous matrix can be observed within the lesion. On MRI, the lesion typically presents as low- to medium-intensity on T1-weighted images and relatively high signal on T2-weighted images. Mild surrounding soft tissue edema or inflammatory changes (“flare phenomenon”) can also be noted, with marked enhancement after contrast administration. Imaging suggests involvement of the adjacent neural foramina, correlating with the patient’s right upper limb pain and decreased muscle strength.
Combining patient age, symptoms, imaging findings, and further confirmation from surgery and pathology, the most likely diagnosis is: Osteoblastoma.
For definitive confirmation, pathological testing is recommended. The patient’s clinical manifestations (progressive pain and neurological compression) and imaging characteristics (lesion larger than 2 cm with osteoid matrix) are consistent with this diagnosis.
1. Treatment Strategy
Although osteoblastoma is a benign tumor, it can enlarge and compress surrounding neural tissues, requiring proactive management. Main treatment options include:
2. Rehabilitation and Exercise Prescription (FITT-VP Principle)
After surgery or treatment, rehabilitation should follow a gradual and individualized approach:
During rehabilitation, close attention should be paid to the affected limb and any changes in pain. If severe pain or neurological symptoms worsen, seek medical evaluation and reassess the rehabilitation strategy. For cervical spine surgery patients, it is crucial to maintain cervical and spinal stability and proceed under professional supervision.
This report provides a preliminary analysis based on the currently available medical history and imaging data. It is for reference only and cannot replace in-person medical evaluation or professional advice. If you have any concerns or if symptoms worsen, please seek medical attention promptly for a more comprehensive and accurate diagnosis and treatment plan.
Osteoblastoma
