Musculoskeletal #24

48-year-old male:
– Heavy smoker
– Depressive syndrome

Found lying unconscious at home, in lateral position (opioid overdose)
Erythema and limited movement of the left shoulder
Blood test: CK 7949 u/l. Negative blood and aspiration cultures (no infection)

What do you see?

Findings

CT: Low attenuation area involving the posterior aspect of the deltoid muscle and the lateral aspect of the pectoralis major muscle. Superficial and deep fascia edema. No enhancing walls neither gas is seen.

MRI: Postcontrast T1FS images show hypointense unenhancing central muscle fibers surrounded by thick rim enhancement involving the posterior deltoid, teres minor, and pectoralis major muscles . Thickened and hyperenhancing adjacent fascia and reactive muscle edema are also noted.

What is the most likely diagnosis?

Rhabdomyolysis (type 2: myonecrosis)
– Injury to skeletal muscle that involves leakage of large quantities of potentially toxic substances into plasma.
– Type 1: homogeneous signal changes and contrast enhancement. Ischemic or reversible ischemic reaction.
– Type 2: homogeneous or heterogeneous signal changes and rim enhancement. Irreversible muscular necrosis (myonecrosis).

– Deep tissue injury: severe pressure ulcer, characterized by necrotic tissue mass under intact skin.

– CK > 1000 – 5000 iu/l “cut-off”.

– Risk factors: postoperative patients (position), obesity, male gender, diabetes, surgical bleeding…

Musculoskeletal #23

89-year-old patient with groin mass

What do you see?

Imaging Findings

Agressive isquion mass with bone destruction, soft tissue component, necrosis and osteid matrix.

In the staging CT: Vertebral and skull signs of paget disease (Bone marrow heterogenity with lytic and sclerotic foci, cortical thikening and bone expansion; as well as partial pagetiic spinal block)

What is the most likely diagnosis?

Diagnosis

Pagetic secondary osteosarcoma on a patient with polyostotic bone paget.

Teaching Points

Osteosarcoma hallmarks are agressive bone mass with osteoid matriz.It can be primary or secondary (mainly on pagetic or radiated bone)
.

Musculoskeletal #22

What do you see?

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Vertebral hemangioma with thickened trabeculae and fat foci inside the lesion, without soft tissue component with an associated pathological fracture.

TEACHING POINTS:
Bone hemangiomas are very frequent, atypical presentations and complications (like in this cases with soft tissue component and pathological fracture) are rare but radiologist must be aware of them to be able to make the correct diagnosis.

Musculoskeletal #21

65-year-old man. Paraplegia after skiing accident. What do you see?

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Imaging findings

Complete low dorsal transdiskal and transvertebral fracture with extension to middle and posterior columns on an ankylosed spine.
Sever posterior angulation and displacement of the superior segment cord deformity, compression and myelopathy.

Diagnosis

Severe complete unstable ankylosed spine fracture with cord compression and mielopathy

Teaching points

Ankylosed spine show specific patterns of fracture with: higher tendency to three column involvement, and increased frequency of neurologic complications.

Musculoskeletal #20

72-year-old alcoholic patient with intractable dorsal pain and legs numbness and weakness.

What do you see?

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IMAGING FINDINGS:

Thoracic spine compression fracture with posterior displacement of the posterior wall of the vertebral body compromising the spinal canal, cord compression and associated myelopathy. T2W image shows fluid and hypointense bubble-like artifact consistent with vacuum cleft in the collapsed anterior vertebral body

DIAGNOSIS:

Kümmel disease (osteonecrosis and collapse of the vertebral body)

TEACHING POINTS:

Intravertebral vacuum cleft and fluid within the collapsed vertebral body is a characteristic feature
Differential diagnosis includes a pathologic (tumoral) fracture, and the presence of air strongly favors osteonecrosis

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MR T2-weighted and CT images to highlight the characteristic features of Kümmel disease

Intravertebral fluid seen on T2 image and air on CT image

Musculoskeletal #18 – Flashcard

27-year-old patient with neurofibromatosis-type 1 (NF-1). Bone lesions found on PET-CT

What are the imaging findings?

Multiple bilateral multiloculated eccentric metaphyseal lucent lesions with thin sclerotic rim

What is the most likely diagnosis?

Multiple non-ossifying fibromas in a patient with NF-1

Teaching points

Very common benign lesion in young adults. Tend to heal or involute. Vast majority asymptomatic. Large lesions may be painful or weaken the cortical predisposing to pathological fracture (rare). Multiple in NF-1

Musculoskeletal #17 – Long Case

2-year-old girl, referring to emergency department after a fall.

What do you see?

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– An expansile lytic lesion with ill-defined margins (green arrow) is seen on the diaphysis of fibula.

– Lamellated periosteal reaction (red arrow) suggests an aggressive lesion.

Differential diagnosis of an aggressive lytic lesion in a 2-year-old child includes:
– Osteomyelitis
– Ewing’s sarcoma
– Langerhans cell histiocytosis
– Leukemia/lymphoma

What should be done next?

An MRI scan

Intramedullary hyperintense lesion with extensive surrounding soft tissue and bone marrow edema on coronal STIR image (a) is seen. The lesion is hypointense on T1 WI (b).

Cortical destruction is shown on axial PD image (arrow in c).

Postcontrast coronal (a) and axial fat-suppressed (b) T1-weighted images show extensive enhancement in the lesion and the surrounding soft tissue

Histopathologic examination revealed Langerhans cell histiocytosis.

Langerhans Cell Histiocytosis (LCH)

– 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.

Musculoskeletal #16

63-year-old patient with knee pain. What do you see?

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IMAGING FINDINGS

Lucent distal femur epiphyseal lesion with thin sclerotic borders and rings-and-archs calcifications, characteristic of chondral matrix

What is the most likely diagnosis?

Enchondroma

CASE 2

Malignant counterpart chondrosarcoma in spinous process of lumbar spinal vertebra

What do you see?

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Teaching points

Enchondroma
Characteristic findings: location epiphysis, thin sclerotic borders and rings-and-archs calcifications
It might be indistinguishable from chondrosarcoma on imaging, and pain may raise the latter suspicion
If bone aggressive lysis, striking endosteal scalloping or soft tissue component is present,