29-year-old long-distance athlete presenting with 3 weeks of sciatica associated with an increase of running training loads
What do you see?
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IMAGING FINDINGS:
Unilateral sacral bone edema T2W, STIR hyperintensity associated with hypointense fracture line
DIAGNOSIS:
Fatigue stress fracture
TEACHING POINTS:
The sacrum is a frequent site for stress fractures
They can be related to overload occurring in a healthy bone as in this case, or related to osteoporosis (insufficiency stress fractures) in which cases they tend to be bilateral and “h- shaped”
Lytic lesion on distal fibular metaphysis with well-defined sclerotic borders is seen on both anteroposterior (a) and oblique (b) radiographs
What do you see?
NOF: non ossifying fibroma
– Most common fibrous bone lesion
– Same as fibrous cortical defect but larger version
– If large enough, may cause pathological fractures
– One of DON’T TOUCH lesions
CT scout viewCT soft tissue windowCT bone windowClick here to see the answer
Skull eosinophilic granuloma
Well defined lytic lesion with scalloped edges. It involves both the inner and outer table. Narrow zone of transition, no cortical breakthrough and no soft tissue component.
28 year-old male with a history of shoulder dislocation.
Regarding this image:
What do you see?
Hill-Sachs lesion
* Edema on posterolateral humeral head secondary to compression fracture, well-demonstrated on axial fat suppressed proton density Weighted image
* Secondary to anterior dislocation of shoulder
Regarding this image:
What do you see?
Bankart lesion
* Tear/injury of anteroinferior labrum, well-demonstrated on axial fat suppressed proton density Weighted image
* Secondary to anterior dislocation of shoulder
* May have associated bony component
Frontal x-ray of the right hand Where is the lesion?
Metaphysis of the base of the fourth middle phalanx.
What are the radiological characteristics/findings?
Expansile lytic lesion (bubbly appearance) with narrow zone of transition, no cortical break through, and no soft-tissue component.
What is the differential diagnosis?
Enchondroma: Enchondromas have variable imaging appearances but are typically lytic lesions with non-aggressive features. They could show chondroid calcifications (rings and arcs calcification). But in the hands and feet they are typically purely lytic with no matrix. Eosinophilic granuloma: It mainly involves the diaphysis and does not cross the growth plates. It appears as punched out lytic lesions without sclerotic rim. Imaging appearance in the long bones depends on the phase of the disease which is imaged. It can look aggressive in the initial phase. In the healing phase it can show solid benign periosteal reaction. Fibrous dysplasia.Usually shows ground-glass matrix but may be completely lucent or sclerotic. Well-circumscribed lesions with no periosteal reaction may lead to premature fusion of growth plates leading to short stature in the lower limbs and bowing deformities (Shepherd’s Crook deformity of the femoral neck)
What is the most likely diagnosis?
Diagnosis: Enchondroma
Regarding the diagnosis…
What are the associated syndromes with multiple enchondromas?
Ollier disease: multiple enchondromas are usually confined to one side of the body and limited to the limbs. There is increased risk of chondrosarcoma
Maffucci syndrome: multiple enchondromas with soft-tissue haemangiomas
Axial CT abdomen bone windowAxial CT abdomen soft tissue windowWhere is the lesion?
Left iliac bone
What are the radiological characteristics/findings?
Large lytic lesion with wide zone of transition, cortical destruction, and large soft tissue component.
No specific matrix.
What is the differential diagnosis of an aggressive iliac bone lesion?
* Metastasis
* Plasmacytoma: solitary plasma cell tumor expansile lytic lesion with bone destruction and soft tissue component. Usually shows low signal intensity on T2 with variable post contrast enhancement.
* Chondrosarcoma: malignant cartilage tumor destructive lytic lesion with intralesional rings and arcs calcification (chondroid matrix). High signal intensity on T2.
Periphyseal (both knees) hyperintensity on sagittal fat suppressed T2 Weighted image (a) and Proton Density Weighted image (b) and hypointensity on sagittal T1Weighted image (c) (arrows).
FOPE: Focal periphyseal edema
– Mostly around the knees
– Both genders can be affected during skeletal maturation
– Painful manifestation of physiologic physeal fusion
1. Mixed lytic and sclerotic lesions of the skull (cotton wool appearance).
2. Widening of the diploic space.
3. Frontal bone enlargement giving the appearance of the Tam o’Shanter hat
