Musculoskeletal #30

38-year-old with left knee pain.
Showing multiple images:

Left knee X-ray:

STIR:

What is the most likely diagnosis?

Enchondroma

* Relatively common intramedullary cartilage neoplasms with benign imaging features
* Constitute ~5% (range 3–10%) of all bone tumors and ~17.5% (range 12–24%) of benign bone tumors

What are the radiological features?

Radiological features

* Narrow zone of transition
* Sharply defined margins
* Chondroid calcification, however, purely lytic in the hands/feet
* Sometimes expansile – more commonly in hands/feet
* Mild endosteal scalloping
* Do not “grow” through cortex (unless pathologic fracture)
* No bone destruction
* No periosteal reaction
* No soft tissue mass

What may be the complications?

Complications

* Pathological fracture
* Malignant transformation into chondrosarcoma

Differential diagnosis includes..

Differential diagnosis

* Bone infarct
* Chondrosarcoma
* Intraosseous ganglion

References

* Murphey MD, Flemming DJ, Boyea SR et-al. Enchondroma versus chondrosarcoma in the appendicular skeleton: differentiating features. Radiographics. 18 (5): 1213-37. Radiographics (abstract) – Pubmed citation
* Walden MJ, Murphey MD, Vidal JA. Incidental enchondromas of the knee. AJR Am J Roentgenol. 2008;190 (6): 1611-5. doi:10.2214/AJR.07.2796 – Pubmed citation
* Douis H, Saifuddin A. The imaging of cartilaginous bone tumours. I. Benign lesions. Skeletal Radiol. 2012;41 (10): 1195-212. doi:10.1007/s00256-012-1427-0 – Pubmed citation
* Mulligan ME. How to Diagnose Enchondroma, Bone Infarct, and Chondrosarcoma. (2019) Current problems in diagnostic radiology. 48 (3): 262-273. doi:10.1067/j.cpradiol.2018.04.002 – Pubmed

Musculoskeletal #29

30-year-old male:

· Persistent pain in his right ankle, for a year long, a synovial mass was demonstrated on ultrasound. · Ankle MRI was performed

What do you see?

Pigmented villonodular synovitis (diffuse articular form)

* Benign proliferative condition affecting the synovial membrane. Most commonly monoarticular
* MRI: Mass-like synovial proliferation with lobulated margins and articular erosions
– Signal -> T1: low-intermediate ; DPFS/STIR: heterogeneous with areas of high signal ; GE: blooming artifact ; T1GD: variable enhancement.

What is the differential diagnosis?

Differential diagnosis includes:
* Scarring – capsulitis
* Siderotic synovitis
* Synovial sarcoma

Musculoskeletal #28

Prune Belly Syndrome

What are the features?

Features

There are three cardinal features:
– Bilateral undescended testicles
– Dilated urinary tract
– Deficient abdominal wall musculature.

These manifestations place patients with prune belly syndrome at risk for testicular malignancy, infertility, urinary tract infections, and renal failure.

The Prune Belly syndrome is also known as:
– Eagle-Barrett syndrome
– Abdominal musculation syndrome

What is the incidence of PBS?

– PBS has a contemporary incidence of 3.6–3.8 per 100,000 live male births
– It is a predominantly male diagnosis as <5% of those diagnosed are female

What are the major manifestations of PBS, giving rise to its alternative name of the triad syndrome?

– A deficiency of abdominal musculature leading to a wrinkled “prune- like” appearance of the abdominal wall.
– Bilateral intra-abdominal testes.
– Urinary tract dysmorphism. The urinary tract anomalies are characterized by differing degrees of renal dysplasia, hydronephrosis, dilated tortuous ureters, an enlarged bladder and a dilated prostatic urethra.

What percentage of patients with PBS are female? What are the major manifestations of PBS in a female?

– Only 5% of PBS diagnoses are female.
– Females exhibit only deficiency of abdominal wall musculature and the anomalous urinary tract without any gonadal abnormality.

Other abnormalities

– 75% of children with PBS have non-urinary tract abnormalities
– These abnormalities include respiratory (58%, e.g. pulmonary hypoplasia), cardiac (25%, e.g. patent ductus arteriosus, atrial septal defect, ventricular septal defect, tetralogy of Fallot), gastrointestinal (63%, e.g. constipation, incomplete rotation of the midgut) and musculoskeletal anomalies (65%, e.g. talipes equinovarus, scoliosis, hip dysplasia)

What is the incidence of prematurity

The incidence of prematurity in the PBS population is nearly 50%.

What is the perinatal mortality of those born with PBS?

– Perinatal mortality ranges between 10 and 29% in contemporary studies.
– Perinatal mortality is directly connected to the level of prematurity and severity of pulmonary hypoplasia.

What is the most common urinary tract abnormality?

Hydroureteronephrosis is almost always present and most commonly bilateral.
– The distal ureter is usually where massive dilation occurs; however the presentation is variable.
– Hydroureteronephrosis is almost never due to obstruction within the ureter, rather, lower urinary tract obstruction (posterior urethral valves), vesicoureteral reflux, and a histologic deficiency of smooth muscle and preponderance of fibrous tissue in the ureters leading to ineffective peristalsis

Musculoskeletal #27

53-year-old female:

– Chronic sensory polyneuropathy (autoimmune). Long-term corticosteroid therapy.
Forefoot pain for three weeks (acute onset without trauma).
– Physical examination: no haematoma , mild swelling.
X-ray performed on day 2 after initial pain.
MRI performed on day 25 after initial pain.

What are the findings?

X-Ray: No obvious fracture.

MRI:
– Bone marrow heterogeneous oedema within the third metatarsal diaphysis (hypointense on T1W image, hyperintense on Proton Density (PD) FatSat image).
Linear low signal intensity fracture identified in all sequences.
Periosteal reaction due to callus formation. Periosteal thickening and enhancement (contrast administration is not necessary for diagnosis).
– Surrounding soft-tissue oedema (adjacent fat and interosseous muscles).

Metatarsal stress fracture (“march fracture”)

– Stress fractures are caused by overuse and repetitive activity.
– Everyday activities may result in a stress fracture if there is any disease or therapy that weakens the bone such as osteoporosis or long-term use of steroids (bone insufficiency: long-term treatment with steroids in this case).
– Classically affects the 2nd or 3rd metatarsal of the foot “march fracture”: named after its prevalence in soldiers who often undertake repeated and prolonged periods of walking as part of their training or work.
– Bone changes are usually not evident on X-rays before 10 to 21 days following the injury. May not be visible for several weeks later, until callus bone formation (the sensitivity range, for detecting stress fractures on initial examinations, is 15-35%; it increases to 30-70% at follow-up studies due to bone reaction).

MRI findings:
– The fluid-sensitive sequences (T2-weighted images with chemically selective fat suppression or STIR sequences) are very useful for the detection of the earliest changes of stress reaction, such as periosteal reaction, muscle, or bone marrow oedema.
– T1-weighted sequences depict the anatomy and more advanced stress-related findings.

Grading based on MRI (Arendt and Griffiths)🙂
1: Mild – moderate periosteal oedema on STIR, no marrow changes.
2: Moderate – severe periosteal oedema on STIR + marrow changes on T2-weighted.
3: Grade 2+ marrow changes on T1-weighted.
4: Fracture line visible.

Musculoskeletal #26

Describe the abnormality

Bilateral sacroiliac joint space narrowing, subchondral erosions, subchondral sclerosis, and subchondral fatty marrow infiltration.

What is the differential diagnosis?

Bilateral symmetrical:
Ankylosing spondylitis
Inflammatory bowel disease. 

Bilateral asymmetrical:
Psoriasis
Reactive arthritis (Reiter syndrome) 

What is the most likely diagnosis?

Ankylosing spondylitis

What are the markers of active inflammation?

Erosions with high signal intensity on STIR or T2- weighted images, subchondral edema, and enhancement within or adjacent to the sacroiliac joint.

What are the markers of chronic disease?

Low signal intensity on T1- and T2- weighted images, subchondral sclerosis, narrowing of the joint spaces, bone bridging, and ankylosis.

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.