A 45-year-old man presented with gradually progressive paraparesis associated with deforming multiple painful swellings involving the chest and back.
On clinical examination multiple hard bony swellings were palpable along the ribs bilaterally in the trunk.
X-ray of the dorsolumbar spine shows expansile lytic lesions with intact sclerotic cortices involving multiple bilateral ribs. (Fig.1)
CT demonstrated lesions with ground glass matrix involving body and posterior appendages of the cervicodorsal, lumbar, sacral segments, multiple thoracic ribs and left scapula. No evidence of abnormal soft tissue mass or periosteal reaction of the involved bones were noted. (Fig. 2, 3, 4)
MRI revealed multiple expansile multiloculated solid-cystic lesions involving lower cervical and upper dorsal vertebrae, their posterior elements with extension into pre & paravertebral regions, multiple bilateral upper ribs, left scapula. The solid components were heterogeneously hyperintense in T2, hypointense on T1 WI showing heterogeneous enhancement in post-contrast study. Few areas of cystic components showed fluid signal. (Fig. 5) Prevertebral and epidural extension posteriorly causing secondary spinal canal stenosis at D2 & D3 levels causing compressive cord myelopathy. Collapse of D3 causing gibbus with kyphotic deformity of the dorsal spine at this level. (Fig. 6, 7)
Fibrous Dysplasia (FD) is a benign skeletal disorder where fibro-osseous tissue replaces the normal medullary space of bone. Classified into two types: monostotic fibrous dysplasia and polyostotic fibrous dysplasia (PFD) which is more symptomatic. The lesions are usually homolateral, monomelic in distribution. [1, 2]
Most patients present in early adolescence with variable symptoms like pain, swelling, deformity or pathological fracture, though patients with PFD usually present in their first decade. No sexual predilection has been reported. [1, 2]
Fibrous dysplasia is known in association with many disorders like McCune-Albright syndrome, hyperparathyroidism, acromegaly, diabetes mellitus, Cushing syndrome associations, soft-tissue myxomas. [1, 2]
Most common sites of involvement are femur, tibia, pelvis; while ribs, skull & upper extremity bones are involved with intermediate frequency; and rarely lumbar spine, clavicle and cervical spine. [1]
Isolated spinal involvement without lesions elsewhere in appendicular skeleton have been reported. 72% of lesions are localized in 1 or 2 sites of the spine, extensive spinal disease is less frequent. Strong correlation reported between spinal lesions and scoliosis. [3]
CT features of FD are ground glass, sclerotic, rarely radiolucent/cystic. CT is indicated for involvement of skull base, to assess cranial foraminas, spinal lesions complicated by fractures and in evaluating lesions with suspected sarcomatous transformation. [4]
MR findings of PFD are variable and not as characteristic as CT findings. While increased fibroblastic activity is seen as hypointense on T1&T2 sequences, the regions with cystic/necrotic degeneration, high cellularity and increased chondroid matrix cause hyperintense images on T2W with generally heterogeneous contrast enhancement. MR images in different planes help to evaluate the extent of PFD, demonstrate neurological complications but for follow up, however, their diagnostic specificity is limited by the presence of similar features in other diseases. [5, 6]
The lesions of FD show avid uptake in early perfusion and late phase on bone scintigraphy. Bone scintigraphy is useful in determining the extent of the disease and in identifying subtle lesions. [1]
Though incidence of malignant transformation is rare, lesions with suspicious clinical signs need to be followed-up by MR and should be compared with prior imaging. [1, 2]
Spinal involvement in fibrous dysplasia is rare; we need to look for associated findings in PFD. Although diagnosis can be made on radiography, CT/MRI have specific indications and are complementary for preoperative evaluation.
Polyostotic fibrous dysplasia
1. The images reveal multiple bony expansive lesions on both sides of the thoracic cage and the back, predominantly involving the ribs. Parts of the vertebral bodies and paravertebral bony structures also show abnormal changes.
2. On X-ray and CT images, the lesions present as “ground-glass” density areas with multiple zones of thickened or sclerotic bone. Locally, there is uneven thinning, expansion, and deformation of the bony cortex, but no definitive cortical disruption or signs of pathological fracture are observed.
3. MRI shows predominantly mixed signals in the lesions, with low intensity on T1W and mixed high intensity on T2W. Some areas display cystic or necrotic components, and the lesion boundaries are relatively ill-defined.
4. Some lesions involve the paravertebral soft tissues, and signs of spinal cord compression suggest progressive lower limb motor dysfunction (presenting as progressive paraplegia).
Based on the patient’s progressive paraplegia, multifocal skeletal lesions, and “ground-glass” appearance, the most likely diagnosis is Polyostotic Fibrous Dysplasia.
If future clinical or imaging findings suggest a rapid increase in lesion size or malignant features, a pathological biopsy should be performed to exclude a potential malignant transformation.
1. Treatment Strategies
- Conservative Management: For patients without severe deformities or nerve compression, periodic follow-ups are recommended. Ensure adequate calcium and vitamin D intake to maintain bone mass, and manage pain with NSAIDs or analgesics when necessary.
- Surgical Intervention: For those with spinal cord or nerve involvement, severe pain, or deformities, procedures such as decompression, internal fixation, or corrective surgery may be conducted to protect neurological function and prevent pathological fractures.
- Pharmacotherapy: Bisphosphonates (e.g., zoledronic acid) may alleviate bone pain and slow bone remodeling, providing supportive benefits to certain patients.
2. Rehabilitation and Exercise Prescription
- Rehabilitation Goals: Lower the risk of fractures, maintain muscle strength and joint mobility, alleviate or delay paraplegia, and improve overall quality of life.
- Exercise Prescription Principles (FITT-VP):
Disclaimer: This report is provided for reference only and does not replace an in-person consultation or professional medical advice. For any concerns, please consult a specialist or visit a hospital for further evaluation and treatment.
Polyostotic fibrous dysplasia
