– LCH is characterised by idiopathic infiltration and accumulation of abnormal histiocytes within various tissues.
– Bone is the most commonly affected tissue in children, with a predilection for axial bones, and femur is the most commonly affected long bone.
– Radiographic appearance of the lesions depends on the site of involvement and the phase of the disease.
– Skull: Calvarium is more affected than the skull base, typically seen as single or multiple well-defined lytic lesions on radiography; T1 hypointense, T2 hyperintense with significant enhancement on MRI. Temporal bone is the most common affected part of skull base seen as destructive lesions with a soft tissue component.
– Spine: Vertebral bodies are affected with relative sparing of posterior elements. A typical vertebra plana appearance may be encountered with total collapse.
– Long bones: Ill-defined lytic lesions with/without cortical destruction are seen usually located at diaphysis or metaphysis. Periosteal reaction may be present. Extensive bone marrow and soft tissue signal changes on MRI may also be helpful in the diagnosis.
4 images of the right shoulder were obtained (axillar, Y-view, internal rotation, external rotation)
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Right shoulder: There is a nondisplaced fracture involving the inferior aspect of the glenoid, with involvement of the articular surface. Glenohumeral joint shows normal alignment. Acromioclavicular joint is normal. No soft-tissue calcification. No fracture or dislocation
What is the most likely diagnosis?
The most likely diagnosis is Hill-Sachs lesion
Hill-Sachs lesions are a posterolateral humeral head compression fracture. Typically occurs secondary to recurrent anterior shoulder dislocations. It is often associated with a Bankart lesion of the glenoid
These lesions are best seen following relocation of the joint. It appears as a sclerotic line running vertically from the top of the humeral head towards the shaft. A wedge defect may be evident in large lesions. The lesions are better appreciated on internal rotation views
A 43-year-old man with inflammation and lower abdominal pain:
What do you see?
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* Inflammatory wall thickening of the sigmoid colon.
* Multiple diverticula, but one enlarged with thickened enhancing wall (arrow).
* Surrounding haziness of the mesosigmoid fat.
* Peritoneal accentuation
Typical image of diverticulitis, in a typical location with typical presentation
Look for signs of perforation or abscess formation
There is a small lucency anterior to the vestibule, just lateral to the basal turn of the cochlea. Consistent with fenestral otosclerosis.
There are two types of otosclerosis:
1- Fenestral: is the most common type. It involves the bone anterior to the oval window and causes conductive hearing loss.
2- Retro-fenestral: involves the cochlear capsule and causes sensorineural hearing loss.
The two types can occur simultaneously.