Bone Tumors Practice Questions

Q: The most probable diagnosis of the lesion depicted in the X-ray is?

Giant cell tumor of bone. ***Giant cell tumor of bone*** - **Giant cell tumors (GCTs)** typically appear as **expansile, osteolytic lesions** eccentrically located in the **epiphysis or metaphysis** of long bones, often with minimal periosteal reaction. - The characteristic appearance on X-ray is a **soap-bubble or ground-glass lesion** that extends to the subchondral bone, commonly located in the epiphyseal region. - Most common location is the **distal femur, proximal tibia, and distal radius** in **skeletally mature patients** (20-40 years). - The lesion is **eccentric, lytic, and extends to the articular surface**. *Simple bone cyst* - **Simple bone cysts (SBCs)** are typically **unicameral (single-chambered) lucent lesions**, usually found in the **diaphysis or metaphysis** of long bones, especially in children and adolescents. - They often exhibit a **"falling leaf" sign** if a pathological fracture has occurred. - **Not typically epiphyseal** and are **centrally located** rather than eccentric. *Osteoma* - **Osteomas** are benign, slow-growing tumors composed of **dense, compact bone**, usually found on the surface of bones, most commonly in the **skull and facial bones**. - They appear as **dense, radiopaque (sclerotic) lesions** on X-ray, which is opposite to the **lucent appearance** of GCT. - Not typically found in the epiphysis of long bones. *Ewing's sarcoma* - **Ewing's sarcoma** typically presents as a **destructive, permeative lesion** with an **"onion-skin" periosteal reaction** (layers of new bone formation) or a **sunburst appearance**. - Most commonly affects the **diaphysis** of long bones in children and young adults. - Highly malignant tumor with aggressive radiographic features, distinct from the expansile, lytic appearance of GCT. - Often accompanied by a **soft tissue mass**.

Q: Which of the following conditions is least likely to present as an eccentric osteolytic lesion?

Simple bone cyst. ***Simple bone cyst*** - Typically appears as a **central lytic lesion** rather than eccentric, most commonly located in the **proximal humerus** or femur. - It is often asymptomatic and discovered incidentally, which is different from other options that are more active lesions. *Aneurysmal bone cyst* - Presents as an **eccentric**, lytic lesion that is often **expansile**, causing cortical thinning or deformation [1]. - Commonly occurs in adolescents, associated with pain and swelling in the affected area. *Giant cell tumour* - Characterized by a **eccentric osteolytic lesion**, usually located around the **knee joint** (distal femur or proximal tibia) [2,3]. - Although it can be locally aggressive, it often presents with **pain and swelling** [2]. *Fibrous cortical defect* - Usually presents as an **eccentric, well-defined** cortical lesion in children and is considered a benign developmental anomaly [1]. - Commonly found on the **metaphysis** of long bones, often self-resolving without interventions [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1206-1208. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1205-1206. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1206.

Q: What is the most appropriate treatment for a soap bubble appearance at the lower end of the radius?

Excision and bone grafting. ***Excision and bone grafting*** - A **soap bubble appearance** at the lower end of the radius is highly suggestive of a **giant cell tumor (GCT)**, which is locally aggressive and has a high recurrence rate after simple curettage. - **Excision of the tumor and filling the defect with bone graft** is the preferred treatment to reduce recurrence and maintain skeletal integrity. *Local excision* - While local excision might remove the visible tumor, **GCTs are known to recur frequently** (up to 50%) after intralesional treatments like simple curettage. - It does not adequately address microscopic extensions or the risk of **local aggressive behavior**. *Amputation* - **Amputation is an overly aggressive and unnecessary treatment** for a GCT, as it is a benign but locally aggressive tumor. - It would be considered only in rare cases of extensive soft tissue invasion or intractable recurrence, which is not implied by a "soap bubble appearance." *Radiotherapy* - **Radiotherapy is generally not the first-line treatment for GCTs** due to concerns about **malignant transformation** (osteosarcoma) in a small percentage of cases, especially with high doses. - It may be considered for unresectable tumors or recurrent lesions in difficult anatomical locations, or as an adjuvant.

Q: Pediatric patient with an upper humerus lytic lesion and cortical thinning, which among the following is not a treatment modality?

Sclerosant. ***Sclerosant*** - While sclerosants can be used in some vascular lesions or cysts, they are **not a standard or primary treatment modality for an upper humerus lytic lesion** with cortical thinning, which often represents a bone cyst or benign tumor. - Their mechanism of action involves **inducing fibrosis and closing off vascular structures**, which isn't the main goal for common lytic bone lesions in children. *Curettage and bone grafting* - This is a very common and effective treatment for **benign lytic bone lesions** like **unicameral bone cysts (UBCs)** or aneurysmal bone cysts (ABCs). - **Curettage** removes the diseased tissue, and **bone grafting** (autograft or allograft) fills the defect, promoting healing and stability. *Steroids* - **Intralesional steroid injection** is a recognized treatment for **unicameral bone cysts (UBCs)**, especially in actively growing lesions in children. - Steroids help **reduce inflammation and promote resolution** of the cyst lining, often leading to bone healing. *Radiotherapy* - While radiotherapy is used for malignant bone tumors, it is **generally avoided for benign lytic lesions in children** due to concerns about long-term risks like growth disturbance and secondary malignancy. - It might be considered in **recalcitrant or aggressive benign lesions** where other treatments have failed, but it is not a first-line treatment.

Q: Most common site of Ewing's sarcoma?

Shaft of femur. ***Shaft of femur*** - The **diaphysis (shaft)** of long bones, particularly the **femur**, is a classic site for Ewing's sarcoma. - This tumor typically arises in the **medullary cavity** of these long bones. *Pelvis* - While the **pelvis** is a common site for Ewing's sarcoma, it is considered the second most common, after the long bones. - Tumors in the pelvis are often associated with a **worse prognosis** due to late presentation and larger tumor volume. *Shaft of tibia* - The **tibia** can be affected by Ewing's sarcoma, but less frequently than the **femur**. - Like the femur, it typically involves the **diaphysis** of the bone. *Ribs* - **Ribs** are also a possible site for Ewing's sarcoma, especially in older children or adolescents. - However, they are less commonly affected than the major long bones or the pelvis.

Q: Expansile lytic lesion with fluid-fluid levels involving the proximal metaphysis of fibula in an early adolescent female is typical of?

Aneurysmal bone cyst. ***Aneurysmal bone cyst*** - An **expansile lytic lesion** with **fluid-fluid levels** is a classical radiological finding for an aneurysmal bone cyst (ABC). - ABCs often occur in the **metaphysis of long bones** in children and adolescents, fitting the age and location described. *Giant cell tumor* - While a **lytic lesion**, giant cell tumors typically occur in the **epiphysis** of long bones in young adults, usually after skeletal maturity. - Though they can rarely have fluid-fluid levels, they are not the typical presentation in an early adolescent. *Fibrous dysplasia* - This condition presents as a **ground-glass matrix** on imaging, often with an expansile appearance, but it typically lacks **fluid-fluid levels**. - It is a developmental anomaly where normal bone is replaced by fibrous tissue and immature bone. *Hemangioma* - Bone hemangiomas are less common in long bones and usually present as a **lytic lesion** with a characteristic **honeycomb or spoked-wheel pattern**. - They do not typically show prominent **fluid-fluid levels** in an expansile lesion.

Question 1

The most probable diagnosis of the lesion depicted in the X-ray is?

Accepted Answer

Giant cell tumor of bone

Answer

Simple bone cyst

Answer

Osteoma

Answer

Ewing's sarcoma

Question 2

Which of the following conditions is least likely to present as an eccentric osteolytic lesion?

Accepted Answer

Simple bone cyst

Answer

Aneurysmal bone cyst

Answer

Giant cell tumor

Answer

Fibrous cortical defect

Question 3

What is the most appropriate treatment for a soap bubble appearance at the lower end of the radius?

Accepted Answer

Excision and bone grafting

Answer

Local excision

Answer

Amputation

Answer

Radiotherapy

Question 4

Pediatric patient with an upper humerus lytic lesion and cortical thinning, which among the following is not a treatment modality?

Accepted Answer

Sclerosant

Answer

Curettage and bone grafting

Answer

Steroids

Answer

Radiotherapy

Question 5

Most common site of Ewing's sarcoma?

Accepted Answer

Shaft of femur

Answer

Pelvis

Answer

Shaft of tibia

Answer

Ribs

Question 6

Expansile lytic lesion with fluid-fluid levels involving the proximal metaphysis of fibula in an early adolescent female is typical of?

Accepted Answer

Aneurysmal bone cyst

Answer

Giant cell tumor

Answer

Fibrous dysplasia

Answer

Hemangioma

Bone Tumors — MCQs

Bone Tumors — MCQs

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