SCLEROTIC BONE LESIONBy Dr. KM Liau
Generally bone sclerosis signifies a slow-growing process. Bone reacts to disorder in two ways -- either by removing some of itself or by creating more of itself. If the disorder is rapidly progressive, there may only be time for retreat, hence bone resorption will occur giving rise to lytic lesion . If the process is slower growing, then the bone may have time to defend itself by forming a sclerotic border around the offender.
UNIVERSAL DIFFERENTIAL DIAGNOSIS
1. Vascular - hemangiomas, infarct(sickle cell).
2. Infection - Chronic osteomyelitis
---A) Primary - Osteoma, Osteosarcoma
---B) Metastatic - Prostate, Breast
4. Drugs - Vitamin D, fluoride
6. Congenital - Osteopoikilosis, Osteopetrosis
8. Trauma - Stress fracture
9. Endocrine/metabloic - Hyperparathyroidism, Paget's disease
Approximately 50% of osseous hemangiomas are found in the vertebral bodies (thoracic especially) and 20% in the calvarium.
The remaining lesions are found in the tibia, femur and humerus.
* Marrow Hyperplasia
* Spontaneous Fracture
* Growth Disturbance
* Arthritis (septic-reactive)
X ray finding:
* Thinning of cortex
* Dense amorphous chalky zones ( Infarcts )
SICKLE ANAEMIA WITH AVN OF HEAD OF FEMUR
Patchy sclerosis is particularly marked over the proximal femoral metaphyses and diaphyses.
There is a bone-within a bone appearance, particularly in the diaphysis of the left femur that implies an intermittent process.
The head of the left femur is flattened and broadened.
The curvatures of both surfaces of the left hip no longer correspond as the centre of the neck of left femur has migrated upwards and outwards.
The right hip joint surfaces are congruent, despite the sclerosis of that femoral head.
There is osteophytic lipping at the margins of the acetabulum on both sides.
Diagnosis: AVN of Left Head of Femur Ficat Stage 4
The metaphyseal area of long bones, the clavicle, and the shoulder girdle are common locations.
Osteoid osteoma has a distinct clinical picture of dull pain that is worse at night and disappears within 20 to 30 minutes of treatment with non-steroidal anti-inflammatory medication.
4 diagnostic features include
(1) a sharp round or oval lesion
(2) less than 2 cm in diameter,
(3) has a homogeneous dense center
(4) a 1-2 mm peripheral radiolucent zone.
1. Osteoblastic (bone forming)
(note a rare variant which is osteolytic and
resemble aneurysmal bone cyst - telangiectatic
2. Sun ray spicules (Radial ossification) and Codmans triangle (lifting of periosteum)
3. Wide zone of transition.
4. Cortical breach common
5. Adjacent soft tissue mass
6. Joint space rarely involved
Always do a per rectal examination (or be prepared to get screwed!!!)
They can present either as lytic or blastic lesion.
The picture shows blastic lesion over L1, L2, L3 vertebrae.
There is a widespread patchy increase in bone density with ossification of capular ligament insertions of hip and intervertebral joints and particularly of the sacro-iliac joints.
Defective osteoclast function with failure of proper reabsorption produces sclerotic bone
Structurally weak bone.
Cortical thickening with medullary encroachment
Erlenmeyer flask deformity = clublike long bones due to lack of tubulization + flaring of ends
"Sandwich" vertebrae=alternating sclerotic + radiolucent transverse metaphyseal lines (phalanges, iliac bones) indicate fluctuating course of disease
Longitudinal metaphyseal striations
Note the fine lucent line involving 1 cortex only and mild periosteal reaction.
Abscence of lytic or blastic lesion and normal medullary canal rules out other pathologies.
Calcified deposits around joints may mimic tumoral calcinosis (Picture)
NOTe: Brown tumors due to primary hyperparathyroidism are LYTIC and they are less common.
Very rare in Malaysia.
* Classical triad of:
o Thickening of the cortex
o Accentuation of the trabecular pattern
o Increased size of bone
Associated neoplasia (0.7-20%)
* Sarcomatous transformation into osteosarcoma (22-90%)
* Fibrosarcoma /malignant fibrous histiocytoma (29-51%)
* Chondrosarcoma (1-15%)