53-year-old male:
– Persistent right shoulder pain, no movement limitations.
– No previous trauma.
– Shoulder MRI is performed
What do you see?
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Quadrangular/Quadrilateral space syndrome
– Posteroinferior paralabral cyst (arrow) extending into the quadrangular space
– Teres minor mild fatty infiltration – atrophy (circle)
– Neurovascular compression syndrome of the posterior humeral circumflex artery (PHCA) and/or the axillary nerve or one of its major branches in the quadrangular space
– Multiple causes of compression: fibrotic bands, ganglion/cysts, aneurysms, tumours
– MRI may demonstrate atrophy and/or denervation edema of the teres minor and/or deltoid muscles
– Differential diagnosis: Parsonage-Turner sd, disuse atrophy
– Patient with no relevant clinical history
– Parents mention a difficulty when running, the patient trips very easily and sometimes struggles to use the right leg. The right leg is often painful
Showing the X-ray right knee and the pelvis
What do you see?
X-ray right knee
Eccentric, lytic bone lesions with sharp margins
No periosteal reaction
Ground-glass matrix of the lesion in the right tibial diaphysis
Soap-bubbly appearance of the lesion in the femoral diaphysis
X-ray pelvis
Expansile bone lesion with ground glass matrix in the right femoral neck, extending into the proximal diaphysis
Slight varus deformity of the femoral neck
Similar lesion in the right iliac wing/acetabular region
A CT was performed:
Showing X-ray of both feet.
What do you see?
Expansile bone lesion with ground glass matrix involving the 1st metatarsal and proximal and distal phalanges of the left foot
Soap-bubbly lesions of the talus and 5th metatarsal
What is your diagnosis?
Imaging findings:
– Multiple bone lesions with benign appearance
– Expansile lesion with ground-glass matrix in the femoral neck virtually pathognomonic for fibrous dysplasia
– Genetic testing could not reveal mutations of the GNAS gene: no syndromic association in this patient
Teaching points
Teaching points:
Benign bone lesions
– Usually central in bone
– Varying degrees of expansion
– Ground-glass matrix (mildly sclerotic)
– Lack of aggressive features (no periosteal reaction, no cortical breakthrough or soft tissue mass) Aetiology: developmental dysplasia Fibrous dysplasia is polyostotic in 15–20%, often in syndromic association (mutations of the GNAS gene)
– McCune-Albright syndrome (in combination with endocrine dysfunctions)
– Mazabraud syndrome
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
* 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.
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
– 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.
61-year-old female:
– Trauma
– Fracture? What do you see?
Showing the supine AP and lateral view, due to the inability to stand on the right leg.
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Diagnosis: Lipohemarthrosis (fat-blood level) indicating intra-articular #
Comminutive though non-displaced tibia plateau fracture Avulsion fracture proximal fibula (Segond fracture – 100% association with ACL injury)
CT: Schatzker type VI
Schatzker tibia plateau classification
– Schatzker I:wedge-shaped pure cleavage fracture of the lateral tibial plateau, having less than 4 mm of depression or displacement
– Schatzker II:splitting and depression of the lateral tibial plateau; namely, type I fracture with a depressed component
– Schatzker III:pure depression of the lateral tibial plateau; divided into two subtypes:
– Schatzker IIIa: with lateral depression
– Schatzker IIIb: with central depression
– Schatzker IV:medial tibial plateau fracture with a split or depressed component
– Schatzker V: wedge fracture of both lateral and medial tibial plateau
– Schatzker VI:transverse tibial metadiaphyseal fracture, along with any type of tibial plateau fracture (metaphyseal-diaphyseal discontinuity)
Sclerotic lesion arising from the outer layer of the left parietal bone with narrow zone of transition. No cortical break through or soft tissue component. The medullary cavity is intact
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.
