Bone Tumors Practice Questions

Q: All the statements are true about exostosis except?

Growth continues after skeletal maturity. **Exostosis**, also known as **Osteochondroma**, is the most common benign bone tumor. It is a developmental anomaly rather than a true neoplasm, characterized by a cartilage-capped bony outgrowth on the surface of the bone. ### **Explanation of Options** * **Correct Answer (B): Growth continues after skeletal maturity.** The growth of an osteochondroma is strictly linked to the activity of the epiphyseal growth plate. Therefore, **growth typically ceases once the person reaches skeletal maturity** (when the growth plates close). If an exostosis starts growing again in an adult, it is a major "red flag" for malignant transformation into a Chondrosarcoma. * **Option A: It occurs at the growing end of bone.** This is true. Exostosis typically arises from the **metaphysis** of long bones (most commonly the distal femur and proximal tibia) near the growth plate. * **Option C: It is covered by a cartilaginous cap.** This is true. The tumor is composed of a bony stalk (pedunculated or sessile) that is continuous with the host bone's cortex and medullary cavity, topped by a **hyaline cartilage cap**. * **Option D: Malignant transformation may occur.** This is true. While rare ( 2 cm** in an adult is highly suggestive of malignancy. 3. **Genetics:** Associated with mutations in **EXT1 and EXT2** genes. 4. **Treatment:** Asymptomatic lesions are managed conservatively. Surgical excision is indicated only if the lesion is painful, interferes with joint movement, or shows signs of malignancy.

Q: What is the most common benign tumor in individuals less than 20 years of age?

Osteochondroma. **Explanation:** **Osteochondroma (Exostosis)** is the most common benign bone tumor overall and specifically in individuals under 20 years of age. It is a developmental anomaly rather than a true neoplasm, characterized by a cartilage-capped bony outgrowth on the surface of the bone. It typically arises from the metaphysis of long bones (most commonly the distal femur) and grows away from the joint. Growth usually ceases once the epiphyseal plates close at puberty. **Analysis of Incorrect Options:** * **Ossifying Fibroma:** This is a rare fibro-osseous lesion, most commonly found in the mandible or craniofacial bones. It is not the most common benign tumor in the pediatric/adolescent age group. * **Chondroblastoma:** While it occurs in young patients (10–20 years), it is a rare tumor. Its defining feature is its **epiphyseal** location (e.g., greater trochanter or proximal humerus), making it a classic "epiphyseal tumor" in children. * **Osteoclastoma (Giant Cell Tumor):** This is typically seen in the **20–40 year** age group (after skeletal maturity). It is an epiphyseal tumor that is locally aggressive and characterized by a "soap bubble" appearance on X-ray. **NEET-PG High-Yield Pearls:** * **Radiology:** Look for "cortical and medullary continuity" with the parent bone. * **Pathogenesis:** Associated with mutations in **EXT1 and EXT2** genes. * **Complication:** Malignant transformation to Chondrosarcoma is rare ( 2 cm** in adults. * **Multiple Hereditary Exostoses (MHE):** An autosomal dominant condition with multiple osteochondromas and a higher risk of malignancy.

Q: Which of the following statements is true regarding osteoid osteoma?

All of the above.. **Explanation:** Osteoid osteoma is a common, benign, bone-forming tumor characterized by a small, well-demarcated core called a **nidus** (less than 2 cm in diameter). * **Option A:** The tumor most frequently involves the long bones of the lower extremities, with the **femur (specifically the neck) and the tibia** being the most common sites (accounting for ~50% of cases). * **Option B:** Radiologically, it presents as a small, **radiolucent nidus** surrounded by a zone of reactive, **dense sclerotic bone**. On CT scans (the gold standard for diagnosis), the nidus may sometimes show a central punctate area of calcification. * **Option C:** The hallmark clinical feature is **nocturnal pain** that is severe and disproportionate to the size of the lesion. This pain is mediated by high concentrations of **prostaglandins** (PGE2) within the nidus and is characteristically relieved by **aspirin or other NSAIDs** within 20–30 minutes. Since all individual statements are accurate descriptions of the pathology, clinical presentation, and radiology of the tumor, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **Age Group:** Typically affects adolescents and young adults (10–25 years). * **Location:** Most are **cortical** in location. * **Spine Involvement:** If it occurs in the spine, it most commonly involves the **posterior elements** (lamina/pedicle) and can cause painful scoliosis. * **Differential Diagnosis:** Must be distinguished from **Osteoblastoma**, which is larger (>2 cm), lacks the dramatic response to aspirin, and has less reactive sclerosis. * **Management:** Medical management with NSAIDs is the first line; if unsuccessful, **Radiofrequency Ablation (RFA)** is the treatment of choice.

Q: Extended curettage is indicated in all the following conditions except:

Unicameral bone cyst. **Explanation:** The core concept behind **Extended Curettage** is the mechanical removal of a tumor followed by the use of **adjuvants** (such as liquid nitrogen, phenol, or high-speed burr) to extend the surgical margin and kill microscopic residual cells. This is indicated for **locally aggressive benign tumors** or those with high recurrence rates. **Why Unicameral Bone Cyst (UBC) is the correct answer:** A UBC is a simple, non-neoplastic serous fluid-filled cavity. It is not locally aggressive. The primary treatment goal is to initiate a healing response, usually via **simple curettage and bone grafting** or minimally invasive techniques like **steroid injections (Methylprednisolone)** or bone marrow aspirate. Adjuvants used in extended curettage are unnecessary and may damage the growth plate in children. **Analysis of Incorrect Options:** * **Giant Cell Tumor (GCT):** This is a locally aggressive tumor with a high recurrence rate (up to 50% with simple curettage). Extended curettage using a high-speed burr and chemical adjuvants is the **standard of care** to reduce recurrence. * **Aneurysmal Bone Cyst (ABC):** Though benign, ABCs are locally destructive and vascular. Extended curettage is preferred to ensure complete removal and prevent recurrence. * **Enchondroma:** While often latent, symptomatic enchondromas or those in specific locations are treated with extended curettage to ensure no cartilaginous matrix remains that could lead to recurrence. **High-Yield Clinical Pearls for NEET-PG:** * **GCT:** Characterized by "Soap Bubble" appearance on X-ray; occurs in the **epiphysis** after skeletal maturity. * **UBC:** Characterized by the **"Fallen Leaf Sign"** (pathological fracture fragment settling at the bottom of the cyst). * **ABC:** Characterized by **"Fluid-Fluid levels"** on MRI. * **Most common site for UBC:** Proximal humerus > Proximal femur.

Q: Codman's triangle is seen in which of the following conditions?

Osteosarcoma. ### Explanation **Codman’s Triangle** is a classic radiological sign representing an aggressive **periosteal reaction**. It occurs when a rapidly growing lesion (usually a tumor) lifts the periosteum away from the bone, leaving a triangular area of new subperiosteal bone at the margin where the periosteum is still attached. #### Why Osteosarcoma is Correct: **Osteosarcoma** is the most common primary malignant bone tumor in adolescents. Because it is highly aggressive and grows rapidly, it frequently breaches the cortex and elevates the periosteum. This results in characteristic periosteal reactions: **Codman’s Triangle** and the **Sunburst (Spiculated) appearance**. #### Why Other Options are Incorrect: * **Chondroblastoma:** A benign, epiphyseal tumor typically seen in young patients. It usually presents as a well-defined lytic lesion with a "fluffy" or "popcorn" calcification, but lacks aggressive periosteal reactions. * **Chondrosarcoma:** While malignant, it often presents in older adults with "endosteal scalloping" and "ring-and-arc" calcifications. While it can show periosteal changes, it is less classically associated with Codman’s Triangle than Osteosarcoma. * **Giant Cell Tumor (GCT):** A "benign but locally aggressive" tumor located in the epiphysis (extending to the subchondral bone). It typically shows a **"Soap-bubble appearance"** and lacks a periosteal reaction because it expands the bone rather than lifting the periosteum abruptly. #### NEET-PG High-Yield Pearls: * **Codman’s Triangle** is not pathognomonic for Osteosarcoma; it can also be seen in **Ewing’s Sarcoma**, subacute osteomyelitis, and active hematomas. * **Ewing’s Sarcoma** is more classically associated with an **"Onion-skin"** (lamellated) periosteal reaction. * **Osteosarcoma** most commonly occurs around the knee (distal femur/proximal tibia) and is associated with a rise in **Serum Alkaline Phosphatase**.

Q: What is the characteristic location of Ewing's sarcoma?

Diaphysis. **Explanation:** **Ewing’s Sarcoma** is a highly malignant primary bone tumor typically seen in children and adolescents (5–15 years). The characteristic location is the **Diaphysis** (shaft) of long bones, most commonly the femur, tibia, and humerus. **Why Diaphysis is correct:** Ewing’s sarcoma originates from the marrow cavity (neuroectodermal origin). Unlike many other bone tumors that arise from the growth plate regions, Ewing’s has a predilection for the mid-shaft. The tumor cells permeate the Haversian canals, reaching the subperiosteal space and triggering a characteristic "onion-skin" periosteal reaction. **Why other options are incorrect:** * **Epiphysis:** This is a rare site for tumors. The classic "epiphyseal" tumors are Giant Cell Tumor (GCT) in adults and Chondroblastoma in children. * **Metaphysis:** This is the most common site for most primary bone tumors (e.g., Osteosarcoma, Osteochondroma, and Aneurysmal Bone Cyst) due to high metabolic activity and cell turnover. Ewing’s is a notable exception to this rule. **High-Yield Clinical Pearls for NEET-PG:** * **Radiology:** Classic "Onion-peel" appearance (concentric layers of new bone formation). * **Histology:** Small, round, blue cell tumor with PAS-positive (diastase sensitive) cytoplasm due to glycogen. * **Genetics:** Associated with **t(11;22)** translocation, leading to the **EWS-FLI1** fusion gene. * **Clinical Presentation:** Often mimics osteomyelitis (fever, raised ESR, local swelling, and pain). * **Markers:** CD99 (MIC-2) positive.

Q: What is the most common primary malignant bone tumor?

Multiple myeloma. **Explanation:** The correct answer is **Multiple Myeloma**. In the context of bone tumors, it is essential to distinguish between "primary malignant bone tumors" (which include hematological malignancies arising in the bone marrow) and "primary malignant non-hematopoietic bone tumors." 1. **Why Multiple Myeloma is correct:** Multiple myeloma is a plasma cell dyscrasia that arises within the bone marrow. Epidemiologically, it is the **most common primary malignancy of bone** overall. In NEET-PG, if the question does not specify "non-hematopoietic" or "matrix-forming," Multiple Myeloma remains the top choice. It typically affects adults over 50 years of age and presents with "punched-out" lytic lesions. 2. **Why the other options are incorrect:** * **Osteosarcoma:** This is the most common primary **non-hematopoietic** (or bone-forming) malignant bone tumor. It is the most common primary malignancy in children and adolescents, but second to Multiple Myeloma in the general population. * **Osteochondroma:** This is the most common **benign** bone tumor. It is a developmental outgrowth (exostosis) rather than a malignancy. * **Osteoclastoma (Giant Cell Tumor):** This is a "locally aggressive" tumor, usually considered benign but with potential for recurrence and rare metastasis. It is not the most common malignancy. **NEET-PG High-Yield Pearls:** * **Most common bone tumor overall:** Metastatic bone disease (Secondary). * **Most common primary bone malignancy:** Multiple Myeloma. * **Most common primary bone malignancy (excluding hematological):** Osteosarcoma. * **Most common benign bone tumor:** Osteochondroma. * **Age Factor:** If the patient is >40 years, think Metastasis or Multiple Myeloma; if <20 years, think Osteosarcoma or Ewing’s Sarcoma.

Question 1

All the statements are true about exostosis except?

Accepted Answer

Growth continues after skeletal maturity

Answer

It occurs at the growing end of bone

Answer

It is covered by a cartilaginous cap

Answer

Malignant transformation may occur

Question 2

What is the most common benign tumor in individuals less than 20 years of age?

Accepted Answer

Osteochondroma

Answer

Ossifying fibroma

Answer

Chondroblastoma

Answer

Osteoclastoma

Question 3

In which of the following conditions may pulsations or murmur be detected?

Accepted Answer

Capillary hemangioma

Answer

Osteogenic sarcoma

Answer

Epidermoid carcinoma

Answer

Osteoid osteoma

Question 4

Which of the following statements is not true about osteoid osteoma?

Accepted Answer

The lesion appears ill-defined on x-ray with permeative margins.

Answer

It is the most common true benign tumor of bone.

Answer

It typically occurs between 10 - 30 years of age.

Answer

Bone scan demonstrates increased uptake in the lesion.

Question 5

Which of the following statements is true regarding osteoid osteoma?

Accepted Answer

All of the above.

Answer

The femur and tibia are the commonest bones involved.

Answer

Radiologically appears as a radiolucent lesion surrounded by dense bone.

Answer

It is a benign bone tumor that presents with severe pain typically relieved by aspirin.

Question 6

Extended curettage is indicated in all the following conditions except:

Accepted Answer

Unicameral bone cyst

Answer

Aneurysmal bone cyst

Answer

Enchondroma

Answer

Giant cell tumor

Question 7

Codman's triangle is seen in which of the following conditions?

Accepted Answer

Osteosarcoma

Answer

Chondroblastoma

Answer

Chondrosarcoma

Answer

Giant Cell Tumor

Question 8

What is the characteristic location of Ewing's sarcoma?

Accepted Answer

Diaphysis

Answer

Epiphysis

Answer

Metaphysis

Answer

Any of the above

Question 9

What is the most common primary malignant bone tumor?

Accepted Answer

Multiple myeloma

Answer

Osteosarcoma

Answer

Osteochondroma

Answer

Osteoclastoma

Question 10

A 15-year-old boy reports with a rapidly growing swelling of the mandible with intermittent pain. Radiographs reveal formation of new subperiosteal bone producing an 'onion skin' appearance. The patient also has lip paresthesia and an elevated white blood cell count. Which of the following statements is true for Ewing's sarcoma?

Accepted Answer

An episode of trauma often precedes the development of Ewing's sarcoma.

Answer

Trauma is the main etiology in the development of Ewing's sarcoma.

Answer

A relationship between trauma and Ewing's sarcoma has never been reported.

Answer

Trauma can be considered as an etiology for Ewing's sarcoma provided there is secondary infection.

Bone Tumors — MCQs

Bone Tumors — MCQs

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