Musculoskeletal Radiology Practice Questions

Q: Which of the following statements about lipoma is radiologically true?

Low attenuation on CT scan. ***Low attenuation on CT scan*** - Lipomas, being composed of **fat**, appear as areas of **low attenuation** (typically -50 to -150 Hounsfield Units) on computed tomography (CT) scans. - This low attenuation is a **key diagnostic characteristic** that helps differentiate lipomas from other soft tissue masses. *Hyperechoic on ultrasound* - Lipomas typically appear **isoechoic to hypoechoic** on ultrasound, not consistently hyperechoic. - They may have a thin echogenic capsule, but the internal contents are usually similar to or less echogenic than adjacent subcutaneous fat. *Hyperintense on fat-suppressed sequences* - This is **incorrect** - lipomas show **signal dropout** (become dark/hypointense) on fat-suppressed sequences (STIR, fat-sat T1/T2). - Signal suppression on fat-saturated sequences is actually a **diagnostic feature** confirming the fatty nature of the lesion. - Note: Lipomas ARE hyperintense on standard T1-weighted imaging due to fat content. *Hyper-intense on T2-weighted MRI* - Lipomas typically show **intermediate to slightly hyperintense signal** on T2-weighted MRI, but not markedly hyperintense like fluid. - They are less bright than fluid-filled structures or highly vascular lesions on T2-weighted sequences.

Q: What type of lesions in the skull bones can be identified on this X-ray?

Paget's disease. ***Paget's disease*** - An X-ray of the skull in Paget's disease typically shows **thickening of the skull vault** and areas of both **osteolysis** and **osteosclerosis**, leading to a characteristic "cotton wool" appearance. - The disease involves abnormal bone remodeling, leading to enlarged and weakened bones susceptible to deformity and fracture. *Multiple myeloma* - On a skull X-ray, multiple myeloma usually presents as multiple, sharply-defined, **"punched-out" lytic lesions** without a sclerotic border. - These lesions reflect areas where malignant plasma cells have destroyed bone, which is distinct from the mixed lytic and sclerotic changes of Paget's disease. *Osteosarcoma* - Osteosarcoma is a **primary bone malignancy** that typically presents as a solitary lesion with a mixture of lytic and sclerotic areas, often with a **sunburst or Codman's triangle** periosteal reaction. - It most commonly affects long bones in younger individuals and is a much less common presentation in the skull compared to other bone conditions. *Osteomyelitis* - Osteomyelitis is an **infection of the bone** that would appear on an X-ray as areas of bone destruction (lysis) and new bone formation (sclerosis), often with **sequestrum** (dead bone) and **involucrum** (new bone formation around the infection). - While it can affect the skull, its imaging features would typically be localized signs of infection rather than the widespread, generalized changes seen in Paget's disease.

Q: Which condition is associated with the pencil in cup deformity?

Psoriatic arthritis. ***Psoriatic arthritis*** - The **pencil-in-cup deformity** is a classic radiographic finding in advanced psoriatic arthritis, occurring due to **periarticular bone erosion** and phalangeal telescoping. - This specific deformity is characterized by the proximal phalanx eroding and fitting into the expanded distal phalanx, resembling a "pencil in a cup." *Rheumatoid arthritis* - While rheumatoid arthritis causes significant joint destruction, it typically presents with **periarticular erosions** and **joint space narrowing**, but not the characteristic pencil-in-cup morphology. - Common deformities include **swan-neck** and **boutonnière** deformities, and ulnar deviation. *Ankylosing spondylitis* - This condition primarily affects the **axial skeleton**, leading to spinal fusion and **sacroiliitis**. - Peripheral joint involvement is less common and typically does not result in the pencil-in-cup deformity; instead, it can cause **syndesmophytes**. *Avascular necrosis* - **Avascular necrosis** (AVN) involves the death of bone tissue due to lack of blood supply, primarily affecting the femoral head or other major joints. - Radiographic findings include **subchondral collapse**, crescent sign, and eventual joint destruction, but not the specific deformities seen in inflammatory arthritis like pencil-in-cup.

Q: Which type of arthritis is characterized by the absence of a periosteal reaction?

Neuropathic arthritis. ***Neuropathic arthritis*** - **Neuropathic arthritis** (**Charcot joint**) is characterized by progressive joint destruction due to loss of proprioception and pain sensation, leading to severe bone and joint damage without a typical **periosteal reaction**. - The absence of normal protective reflexes results in repetitive microtrauma, often leading to bone resorption and fragmentation rather than new bone formation (periosteal reaction). *Psoriatic arthritis* - **Psoriatic arthritis** often presents with distinctive **periosteal reactions**, particularly at entheses and along the shafts of small bones (e.g., "pencil-in-cup" deformities and fluffy periostitis) [1]. - These periosteal changes are a hallmark of the inflammatory process affecting bone and connective tissues in psoriatic arthritis. *Rheumatoid arthritis* - **Rheumatoid arthritis** primarily involves the synovium, leading to erosions rather than prominent periosteal reactions in early stages [1]. - While periostitis can occur in chronic, destructive rheumatoid arthritis, it is not a primary or characteristic finding compared to other inflammatory arthritides. *Reactive arthritis* - **Reactive arthritis** frequently causes **periosteal reactions**, particularly at entheses (where tendons and ligaments attach to bone) and along the shafts of long bones, often described as "fluffy" periostitis [1]. - These new bone formations are a key radiological feature distinguishing it from other types of inflammatory arthritis.

Q: What is the condition characterized by a 'dripping candle wax' appearance on the spine?

Melorheostosis. ***Melorheostosis*** - This rare sclerosing bone dysplasia is characterized by **unilateral, linear periosteal bone thickening** that gives the appearance of **"dripping candle wax"** on imaging studies. - The distinctive radiographic finding is due to an overgrowth of cortical bone, often affecting a single limb. *Metastasis* - **Bone metastases** typically present as multifocal lytic or blastic lesions, depending on the primary tumor, rather than a linear, thick "dripping candle wax" pattern. - While they can involve the spine, the radiographic morphology is distinct from the **cortical thickening** seen in melorheostosis. *TB spine* - Tuberculosis of the spine, or **Pott's disease**, primarily causes **vertebral body destruction**, kyphosis, and *paravertebral abscess formation*. - It does not produce the characteristic **"dripping candle wax" appearance** of cortical hyperostosis. *Osteopetrosis* - **Osteopetrosis** (marble bone disease) is characterized by a generalized increase in **bone density** due to defective osteoclast function. - This condition results in uniformly dense and thickened bones, often referred to as **"bone within a bone"** or a **"sandwich vertebrae"** appearance, which differs from the localized, flowing hyperostosis of melorheostosis.

Q: In which condition is the 'Picture frame vertebra' seen?

Paget disease. ***Paget disease*** - The "picture frame vertebra" sign is a classic radiographic finding in **Paget disease**, characterized by **cortical thickening** and sclerosis around the vertebral body circumference, resembling a picture frame. - This appearance is due to the disordered bone remodeling processes (increased osteoclastic bone resorption followed by disorganized osteoblastic new bone formation) characteristic of Paget disease. *Osteopetrosis (marble bone disease)* - Osteopetrosis is characterized by **increased bone density** due to defective osteoclast function, leading to bones that are dense but brittle. - It does not typically present with the specific "picture frame" appearance of individual vertebrae, but rather with diffuse sclerosis of bones. *Ankylosing spondylitis (AS)* - Ankylosing spondylitis primarily affects the **axial skeleton**, causing inflammation and eventual fusion of the vertebrae (leading to a "bamboo spine" appearance). - While it involves the spine, it does not produce the "picture frame" vertebral sign seen in Paget disease. *Osteoporosis* - Osteoporosis is characterized by **reduced bone mass** and microstructural deterioration of bone tissue, leading to increased bone fragility and fracture risk. - Radiographically, it shows **decreased bone density** and possible vertebral compression fractures, which is the opposite of the increased bone density and cortical thickening seen in the "picture frame" sign.

Q: Which condition is characterized by a 'moth-eaten' appearance of the bones?

Multiple myeloma. ***Multiple myeloma*** [1][2] - Characterized by **punched-out lytic lesions** in bones, often described as **moth-eaten** appearance on imaging [1]. - Associated with **elevated serum proteins** and **Bence Jones proteins** in urine, confirming the diagnosis [2]. *Eosinophilic granuloma* - Usually presents with **solitary bone lesions** and is linked to **Langerhans cell histiocytosis** rather than the moth-eaten pattern. - Does not typically cause generalized **lytic bone lesions** seen in cases of multiple myeloma. *Chondromyxoid fibroma* - Generally appears as a **well-defined cortical lesion** and is not associated with a moth-eaten appearance. - It predominantly affects the **metaphysis** of long bones and shows a characteristic **cartilaginous matrix**. *Osteoid osteoma* - Presents with a **nidus** of osteoid formation, leading to localized bone pain, and does not exhibit a moth-eaten consistency. - Tends to cause **cortical bone thickening** rather than the diffuse lytic lesions associated with multiple myeloma. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, p. 608. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 616-617.

Q: Which condition is characterized by a specific radiological appearance resembling a sunburst pattern?

Osteosarcoma. ***Osteosarcoma*** - **Osteosarcoma** is known for its classic radiological findings, including the **sunburst (rising sun)** or **spiculated periosteal reaction**, where new bone forms perpendicular to the cortex. - Another characteristic finding is **Codman's triangle**, which is a triangular elevation of the periosteum visible on X-ray. *Chondrosarcoma* - **Chondrosarcomas** are typically characterized by a **"rings and arcs"** pattern of calcification within the cartilaginous matrix on imaging studies. - They tend to appear as lobular masses with endosteal scalloping and soft tissue components rather than the sunburst pattern. *Ewing's sarcoma* - **Ewing's sarcoma** classically presents with an **"onion skin" (lamellated)** periosteal reaction due to layers of parallel new bone formation. - It often appears as an ill-defined lytic lesion with cortical destruction, differing from the sunburst appearance. *Fibrosarcoma* - **Fibrosarcomas** are typically **lytic lesions** with aggressive cortical destruction and soft tissue involvement. - They generally do not produce characteristic periosteal reactions like the sunburst or onion skin appearance, often presenting as non-specific destructive lesions.

Q: "Sunray appearance" on X-rays is suggestive of:

An Osteogenic sarcoma. ***An Osteogenic sarcoma*** - The **"sunray appearance" (or sunburst)** on X-rays is a classic radiographic finding pathognomonic for **osteosarcoma**, especially in adults and adolescents. - This appearance is due to the **periosteal new bone formation** that grows perpendicular to the bone surface, creating a radiating spicule pattern. *A type of bone cancer that can show various radiographic appearances* - While true that bone cancers can show various appearances, the "sunray appearance" is specific enough to strongly point to a particular type, rather than just a general category. - This option is too broad and does not provide the most precise diagnosis indicated by the specific radiographic sign. *A metastatic tumour in the bone* - Metastatic bone lesions typically present with **lytic (bone destruction)** or **blastic (bone formation)** patterns, or a mixed pattern, but rarely produce the periosteal "sunray" appearance. - The characteristic radiographic finding for metastasis would often involve multiple lesions and different periosteal reactions, such as an **onion skin appearance** in some aggressive cases, but not typically sunray. *An Ewing's sarcoma* - Ewing's sarcoma commonly presents with an **"onion skin" periosteal reaction** due to multiple layers of new bone formation. - While both are primary bone tumors, the radiographic findings are distinctly different, allowing for differentiation.

Q: Which of the following conditions can cause periosteal reactions?

All of the options. ***All of the options*** - **Periosteal reactions** are non-specific findings that indicate periosteal irritation or inflammation, which can be caused by a wide range of pathologies including infection, neoplasia, and trauma. - This option correctly encompasses the various causes listed in the other choices, making it the most accurate answer. *Osteomyelitis* - **Osteomyelitis**, an infection of the bone, can cause inflammation of the surrounding periosteum, leading to periosteal new bone formation. - The type of periosteal reaction can vary, from **lamellated** to **solid**, depending on the chronicity and aggressiveness of the infection. *Syphilis* - **Congenital syphilis** and tertiary acquired syphilis can lead to significant bone involvement, including **periostitis**, which manifests as periosteal reactions. - The classic appearance in children with congenital syphilis is a **wavy** or **irregular cortical thickening** due to widespread periostitis. *Tumor* - Both **primary bone tumors** (e.g., osteosarcoma, Ewing's sarcoma) and **metastatic lesions** can elicit a periosteal response as they invade or irritate the periosteum. - The periosteal reaction in tumors can present as aggressive patterns like a **sunburst** or **Codman's triangle**, indicating rapid bone destruction and new bone formation.

Question 1

Which of the following statements about lipoma is radiologically true?

Accepted Answer

Low attenuation on CT scan

Answer

Hyperechoic on ultrasound

Answer

Hyperintense on fat-suppressed sequences

Answer

Hyper-intense on T2-weighted MRI

Question 2

What type of lesions in the skull bones can be identified on this X-ray?

Accepted Answer

Paget's disease

Answer

Multiple myeloma

Answer

Osteosarcoma

Answer

Osteomyelitis

Question 3

Which condition is associated with the pencil in cup deformity?

Accepted Answer

Psoriatic arthritis

Answer

Rheumatoid arthritis

Answer

Ankylosing spondylitis

Answer

Avascular necrosis

Question 4

Which type of arthritis is characterized by the absence of a periosteal reaction?

Accepted Answer

Neuropathic arthritis

Answer

Psoriatic arthritis

Answer

Rheumatoid arthritis

Answer

Reactive arthritis

Question 5

What is the condition characterized by a 'dripping candle wax' appearance on the spine?

Accepted Answer

Melorheostosis

Answer

Metastasis

Answer

TB spine

Answer

Osteopetrosis

Question 6

In which condition is the 'Picture frame vertebra' seen?

Accepted Answer

Paget disease

Answer

Osteopetrosis (marble bone disease)

Answer

Ankylosing spondylitis (AS)

Answer

Osteoporosis

Question 7

Which condition is characterized by a 'moth-eaten' appearance of the bones?

Accepted Answer

Multiple myeloma

Answer

Osteoid osteoma

Answer

Eosinophilic granuloma

Answer

Chondromyxoid fibroma

Question 8

Which condition is characterized by a specific radiological appearance resembling a sunburst pattern?

Accepted Answer

Osteosarcoma

Answer

Chondrosarcoma

Answer

Fibrosarcoma

Answer

Ewing's sarcoma

Question 9

"Sunray appearance" on X-rays is suggestive of:

Accepted Answer

An Osteogenic sarcoma

Answer

A metastatic tumour in the bone

Answer

An Ewing's sarcoma

Answer

A type of bone cancer that can show various radiographic appearances

Question 10

Which of the following conditions can cause periosteal reactions?

Accepted Answer

All of the options

Answer

Osteomyelitis

Answer

Syphilis

Answer

Tumor

Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology — MCQs

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