Bone Tumors Practice Questions

Q: The given image is an x-ray of a 22-year-old female. What is the probable diagnosis based on the x-ray?

Giant cell tumor. ***Giant cell tumor*** - The X-ray shows a **lytic lesion** in the **distal humeral metaphysis extending into the epiphysis**, which is characteristic of a giant cell tumor. - Giant cell tumors typically occur in **young adults (20-40 years old)**, are often **eccentric with no sclerotic rim**, and can be aggressive, resembling the presented image in a 22-year-old female. *Chondroblastoma* - This typically presents as an **epiphyseal lesion** with a sclerotic rim in patients with **open physes**, usually younger than 20 years. - The lesion in the image appears to extend beyond the epiphysis, and the patient's age (22) makes chondroblastoma less likely as the physes are generally closed. *Osteochondroma* - This is an **exophytic lesion** typically growing away from the joint, characterized by a cartilage cap and continuity of the cortex and medullary cavity with the parent bone. - The image shows an **intraosseous lytic lesion**, not an exophytic bony projection. *Aneurysmal bone cyst* - This lesion often presents as an **expansile, lytic lesion** with internal septations and fluid-fluid levels, more common in the **metaphysis of long bones** in individuals younger than 20. - While aneurysmal bone cysts can be expansile, they typically show a "soap bubble" appearance with prominent internal septations, unlike the more solid-appearing lesion characteristic of giant cell tumor in this patient.

Q: Which of the following statements about aneurysmal bone cyst is false?

Treated by simple curettage. ***Treated by simple curettage*** - Aneurysmal bone cysts (ABCs) have a high recurrence rate with **simple curettage** alone due to their aggressive nature and tendency to bleed. - More extensive treatment options like **extended curettage**, chemical cauterization with **phenol**, cryotherapy, or sometimes even resection are often necessary to prevent recurrence. *Eccentric* - ABCs are typically **eccentric** in their location within the bone, meaning they often arise on one side of the bone rather than centrally. - This eccentric growth pattern is a characteristic radiologic feature that helps differentiate them from other bone lesions. *Expansile & lytic* - ABCs are characteristically **expansile**, causing the bone cortex to thin and balloon out, and are **lytic**, meaning they destroy bone tissue. - Radiographically, this presents as a **bubbly appearance** with visible fluid-fluid levels on MRI, reflecting blood-filled cavities. *Metaphysis of long bones* - Aneurysmal bone cysts commonly occur in the **metaphysis of long bones**, such as the femur and tibia. - While they can affect any bone, this metaphyseal location, particularly in young individuals, is a frequent presentation.

Q: Which of the following bone tumors characteristically presents with nocturnal pain relieved by NSAIDs and shows a radiolucent nidus surrounded by sclerotic bone?

Osteoid osteoma. ***Osteoid osteoma*** - This benign bone tumor is characterized by **nocturnal pain** that is typically **relieved by NSAIDs**, a highly distinctive clinical feature due to prostaglandin production within the nidus. - Radiographically, it presents as a small **radiolucent nidus** (less than 1.5 cm) surrounded by a significant margin of **sclerotic bone**. *Chondrosarcoma* - This is a **malignant cartilage-forming tumor** that usually presents with a dull, aching pain that is often **not relieved by NSAIDs** and may worsen over time. - Radiographically, it appears as a **large, destructive lesion with calcifications**, not a small nidus with surrounding sclerosis. *Enchondroma* - An enchondroma is a **benign cartilaginous tumor** that is typically found in the medullary cavity of long bones, often in the small bones of the hands and feet. - It is usually **asymptomatic** and discovered incidentally, and on imaging, it appears as a **well-circumscribed lytic lesion** without the prominent sclerotic rim or specific nocturnal pain pattern seen in osteoid osteoma. *None of the options* - This option is incorrect because **osteoid osteoma** perfectly matches the clinical and radiographic description provided in the question.

Q: In the context of bone metastasis, which of the following bones is least likely to be a site of metastasis?

Fibula. ***Fibula*** - The **fibula** is not commonly involved in **metastatic disease**, primarily due to its low blood supply compared to other bones. - While it can occasionally show metastatic lesions, it's **rare** when compared to more commonly affected sites. *Humerus* - The **humerus** can be affected by metastasis, often from lung or breast cancers [1], as it is one of the long bones involved in **hematogenous spread**. - Common presentations include **lytic or blastic lesions**, which indicate bone damage from metastatic processes. *Femur* - The **femur** is frequently involved in metastatic lesions, particularly in patients with malignancies like **prostate or breast cancer** [1]. - Symptoms may include **pain** and **pathologic fractures** due to the weakening of the bone structure from metastasis [1]. *Spine* - The **spine** is a common site for metastases, especially from cancers such as **lung, breast, and prostate** [1]. - Bone scans often reveal **vertebral body lesions**, leading to complications like **spinal cord compression** [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 674-675.

Q: Which of the following is true about Giant cell tumor?

Epiphyseal origin. ***Epiphyseal origin*** - Giant cell tumors (GCTs) characteristically arise in the **epiphysis** or **metaphysis** of long bones, often extending into the subchondral bone [1]. - This distinguishes them from many other bone tumors that typically originate in the diaphysis or metaphysis. *Always benign* - While GCTs are predominantly **benign**, they have a significant potential for **local recurrence** and, in rare cases, can undergo **malignant transformation** or metastasize to the lungs. - Therefore, they are considered to have an **intermediate biological potential**, not strictly benign. *Seen in age less than 15 years* - GCTs are most commonly observed in **young adults**, typically between the ages of 20 and 40 years, after **skeletal maturity**. - They are exceedingly **rare** in individuals younger than 15 years, as the epiphyses are still open. *Usually presents as a lytic lesion without a sclerotic rim* - GCTs are indeed **lytic lesions**, appearing as areas of bone destruction without a significant periosteal reaction or sclerosis, giving them a **"soap-bubble" appearance**. - However, they often have a **thin sclerotic rim** in some parts of the lesion, especially at the margins, which helps differentiate them from more aggressive lesions [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. 1205-1206.

Q: Osteoclastoma arises from which part of the bone?

Metaphysis. ***Metaphysis*** - **Osteoclastoma**, also known as a **Giant Cell Tumor of Bone (GCTB)**, classically originates in the **metaphysis** of long bones. - It then often extends into the **epiphysis**, near the articular cartilage, particularly after epiphyseal plate closure. *Epiphysis* - While GCTB can expand into the **epiphysis**, its primary origin is the **metaphysis**. - Tumors primarily arising in the epiphysis are less common for GCTB, though they can eventually involve this region. *Diaphysis* - The **diaphysis** (bone shaft) is an uncommon site for osteoclastoma origin. - Other bone tumors, such as **Ewing sarcoma** or **adamantinoma**, are more characteristic of diaphyseal locations. *None of the options* - This option is incorrect as **metaphysis** is indeed the correct primary site of origin for osteoclastoma. - The distinct location helps differentiate it from other bone lesions.

Q: Osteochondroma arises from which part of the bone?

Metaphysis. ***Metaphysis*** - **Osteochondromas** are outgrowths of bone and cartilage that typically arise from the **metaphyseal regions** of long bones, such as the distal femur, proximal tibia, and proximal humerus. - This region is characterized by active **endochondral ossification**, which is the process interrupted in the formation of ostecochondromas. *Medullary cavity* - The **medullary cavity** contains bone marrow and is not the primary site of origin for osteochondromas, which are exophytic lesions. - While some tumors can extend into the medullary cavity, their origin is generally from the outer bone surfaces rather than the central cavity. *Diaphysis* - The **diaphysis** is the main or mid-section of a long bone (the shaft), and it is primarily composed of compact bone, with less active growth than the metaphysis. - Though osteochondromas can occur in the diaphysis, they are far less common than in the metaphysis, which is the site of rapid bone growth. *Epiphysis* - The **epiphysis** is the end part of a long bone, initially separated from the main bone by cartilage but later fusing with it. - While it's a site of growth, osteochondromas are very rarely found in the epiphysis, as their growth mechanism is more closely linked to the **physeal plate** located in the metaphysis.

Q: What is the most common primary source of metastatic bone tumors in males?

Prostate. ***Prostate*** - **Prostate cancer** is the most common primary source of metastatic bone tumors in males due to its high propensity to **metastasize to bone** and its high prevalence in the male population [1]. - These metastases are typically **osteoblastic**, causing increased bone density visible on imaging. *Liver* - While the **liver** can be a site of metastasis for many cancers, it is not a common primary source for **bone metastases** [2]. - Liver cancer (hepatocellular carcinoma) can metastasize, but bone is not its most frequent distant site. *Bone* - **Bone** itself can be the site of primary bone tumors, such as osteosarcoma or Ewing's sarcoma, but these are **not metastatic bone tumors** in the sense of originating elsewhere [3]. - When cancer originates in the bone, it is a primary bone cancer, not a metastatic one. *Brain* - **Brain tumors** (primary intracranial malignancies) generally have a **low propensity to metastasize** outside of the central nervous system. - While rare cases of brain tumor metastasis to bone can occur, it is not a common event or primary source.

Q: In which of the following conditions are polyostotic lesions not seen?

Osteoid osteoma. ***Osteoid osteoma*** - An **osteoid osteoma** is typically a **solitary bone lesion**, meaning it rarely presents as polyostotic lesions. - It characteristically presents with **nocturnal pain relieved by NSAIDs**. *Hemangioma* - While often solitary, **hemangiomas** can occasionally be **multiple or polyostotic**, especially in syndromes like **Klippel-Trenaunay syndrome**. - These are benign **vascular tumors** that can occur in bone. *Fibrous dysplasia* - **Fibrous dysplasia** can be **monostotic** (single lesion) or **polyostotic** (multiple lesions), with the polyostotic form often part of **McCune-Albright syndrome**. - It involves the replacement of normal bone with **fibrous tissue**. *Multiple myeloma* - **Multiple myeloma** is a **hematologic malignancy** characterized by the proliferation of plasma cells in the bone marrow, leading to **multiple lytic bone lesions** (polyostotic). - These lesions often manifest as **pain**, **pathological fractures**, and **hypercalcemia**.

Q: A 28-year-old skeletally mature patient presents with knee pain. 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 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**.

Question 1

The given image is an x-ray of a 22-year-old female. What is the probable diagnosis based on the x-ray?

Accepted Answer

Giant cell tumor

Answer

Chondroblastoma

Answer

Osteochondroma

Answer

Aneurysmal bone cyst

Question 2

Which of the following statements about aneurysmal bone cyst is false?

Accepted Answer

Treated by simple curettage

Answer

Eccentric

Answer

Expansile & lytic

Answer

Metaphysis of long bones

Question 3

Which of the following bone tumors characteristically presents with nocturnal pain relieved by NSAIDs and shows a radiolucent nidus surrounded by sclerotic bone?

Accepted Answer

Osteoid osteoma

Answer

Chondrosarcoma

Answer

Enchondroma

Answer

None of the options

Question 4

In the context of bone metastasis, which of the following bones is least likely to be a site of metastasis?

Accepted Answer

Fibula

Answer

Femur

Answer

Humerus

Answer

Spine

Question 5

Which of the following is true about Giant cell tumor?

Accepted Answer

Epiphyseal origin

Answer

Seen in age less than 15 years

Answer

Usually presents as a lytic lesion without a sclerotic rim.

Answer

Always benign

Question 6

Osteoclastoma arises from which part of the bone?

Accepted Answer

Metaphysis

Answer

Diaphysis

Answer

Epiphysis

Answer

None of the options

Question 7

Osteochondroma arises from which part of the bone?

Accepted Answer

Metaphysis

Answer

Medullary cavity

Answer

Diaphysis

Answer

Epiphysis

Question 8

What is the most common primary source of metastatic bone tumors in males?

Accepted Answer

Prostate

Answer

Liver

Answer

Bone

Answer

Brain

Question 9

In which of the following conditions are polyostotic lesions not seen?

Accepted Answer

Osteoid osteoma

Answer

Multiple myeloma

Answer

Fibrous dysplasia

Answer

Hemangioma

Question 10

A 28-year-old skeletally mature patient presents with knee pain. 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

Bone Tumors — MCQs

Bone Tumors — MCQs

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