Bone Tumors Practice Questions

Q: Which of the following is NOT a diaphyseal tumor?

Chondroblastoma. **Explanation:** The location of a bone tumor within the long bone (epiphysis, metaphysis, or diaphysis) is a critical diagnostic clue in orthopaedics. **Why Chondroblastoma is the correct answer:** Chondroblastoma is a classic **epiphyseal** tumor. It typically occurs in young patients (10–20 years) before the growth plate closes. It is one of the few tumors that originate in the epiphysis, along with Giant Cell Tumor (which occurs after physeal closure). Because it is epiphyseal and not diaphyseal, it is the correct "NOT" option. **Analysis of Incorrect Options (Diaphyseal Tumors):** * **Adamantinoma:** A rare, slow-growing malignant tumor that almost exclusively involves the **diaphysis of the tibia**. * **Ewing’s Sarcoma:** A highly malignant round-cell tumor that characteristically involves the **diaphysis** of long bones in children. It often presents with an "onion-skin" periosteal reaction. * **Osteoid Osteoma:** While it can occur in various locations, it frequently involves the **cortex of the diaphysis** (especially the femur and tibia), presenting with night pain relieved by aspirin. **NEET-PG High-Yield Pearls:** * **Mnemonic for Diaphyseal Tumors:** "**A E I O U**" — **A**damantinoma, **E**wing’s Sarcoma, **I**sland of bone (Osteoid Osteoma), **O**steoblastoma (can be), **U**nusual (Eosinophilic Granuloma/Lymphoma). * **Epiphyseal Tumors:** Only two major ones to remember: **Chondroblastoma** (Children/Open physis) and **Giant Cell Tumor** (Adults/Closed physis). * **Metaphyseal Tumors:** Most common site for bone tumors (e.g., Osteosarcoma, Osteochondroma).

Q: What is the most common primary site for a metastatic bone tumor in males?

Lung. **Explanation:** The correct answer is **Lung (Option A)**. In clinical practice, while prostate cancer is highly osteophilic (bone-seeking), **lung cancer** is statistically the most common primary malignancy to metastasize to the bone in males. This is due to the high overall incidence of lung cancer and its aggressive hematogenous spread. **Analysis of Options:** * **Lung (Correct):** It is the most common primary source of bone metastasis in men. These lesions are typically **osteolytic** (bone-destroying) and often present with pathological fractures. * **Prostate (Incorrect):** While prostate cancer is the second most common cause and is famous for producing **osteoblastic** (bone-forming) lesions, it ranks behind lung cancer in total metastatic frequency. * **Liver (Incorrect):** Hepatocellular carcinoma (HCC) rarely metastasizes to the bone; it more commonly spreads intrahepatically or to the lungs. * **Kidney (Incorrect):** Renal Cell Carcinoma (RCC) is a frequent cause of bone metastasis (characteristically "blow-out" lytic lesions), but it is less common than lung or prostate primaries. **NEET-PG High-Yield Pearls:** * **Overall (Both Sexes):** Breast cancer is the most common cause of bone metastasis. * **In Females:** Breast > Lung > Thyroid > Kidney. * **In Males:** Lung > Prostate > Kidney > Thyroid. * **Type of Lesion:** * **Pure Osteoblastic:** Prostate, Carcinoid. * **Pure Osteolytic:** RCC, Thyroid, Lung (usually), Multiple Myeloma. * **Mixed:** Breast (most common mixed). * **Commonest Site of Bone Metastasis:** Spine (specifically the thoracic spine) is the most common site, followed by the pelvis and femur.

Q: A 40-year-old female presented with an epiphyseal tumor at the lower end of the radius. What is the most likely diagnosis?

Giant cell tumor. **Explanation:** The correct diagnosis is **Giant Cell Tumor (GCT)**, also known as Osteoclastoma. The key to solving this question lies in the patient’s age and the specific anatomical location of the tumor. **1. Why Giant Cell Tumor is correct:** * **Location:** GCT is characteristically an **epiphyseal** tumor that often extends into the metaphysis after the growth plate closes. The lower end of the radius is the second most common site (after the distal femur/proximal tibia). * **Age:** It typically occurs in skeletally mature adults aged **20–40 years**. * **Radiology:** It classically presents as an eccentric, "soap-bubble" appearance with a narrow zone of transition and no sclerotic rim. **2. Why other options are incorrect:** * **Ewing’s Sarcoma:** This is a tumor of children and adolescents (5–15 years) and is characteristically **diaphyseal** in location. It shows an "onion-skin" periosteal reaction. * **Osteogenic Sarcoma (Osteosarcoma):** While it is the most common primary bone malignancy, it typically affects the **metaphysis** of long bones in a younger age group (10–20 years). It presents with a "sunburst" appearance or Codman’s triangle. * **Chondromyxoid Fibroma:** This is a rare benign tumor that is usually **metaphyseal** and eccentric, typically occurring in the second or third decade of life. **High-Yield Clinical Pearls for NEET-PG:** * **GCT** is "locally aggressive" but usually benign. However, it can metastasize to the **lungs** (benign pulmonary implants). * **Histology:** Shows characteristic multinucleated giant cells scattered against a background of mononuclear stromal cells (the stromal cells are the actual neoplastic component). * **Treatment:** Extended curettage with the use of adjuvants (like liquid nitrogen or phenol) and bone grafting/bone cement (PMMA).

Q: Which among the following is the most common malignancy of bone?

Secondary deposits. **Explanation:** The correct answer is **Secondary deposits (Metastatic bone disease)**. In clinical practice, metastatic tumors originating from primary sites such as the breast, prostate, lung, kidney, and thyroid are far more common than primary bone malignancies. **Breakdown of Options:** * **Secondary deposits (A):** These are the **most common malignant tumors of bone** overall. They typically occur in the older age group and most frequently involve the axial skeleton (spine, pelvis, and ribs) due to the presence of red marrow and the Batson venous plexus. * **Multiple myeloma (B):** This is the **most common primary malignant bone tumor** in adults. While frequent, its incidence is still lower than that of metastatic disease from other organs. * **Osteosarcoma (C):** This is the **most common primary solid (non-hematological) malignant bone tumor**, typically seen in children and adolescents. * **Osteoid osteoma (D):** This is a **benign** bone-forming tumor characterized by a small nidus and nocturnal pain relieved by NSAIDs; it is not a malignancy. **High-Yield Clinical Pearls for NEET-PG:** 1. **Most common bone tumor (overall):** Osteochondroma (Benign). 2. **Most common malignancy of bone:** Secondary deposits. 3. **Most common primary malignancy of bone:** Multiple Myeloma. 4. **Most common primary solid malignancy of bone:** Osteosarcoma. 5. **Commonest site for bone metastasis:** Spine (Thoracic > Lumbar). 6. **Osteoblastic vs. Osteolytic:** Prostate cancer typically causes osteoblastic (sclerotic) metastases, while most others (like lung or thyroid) are primarily osteolytic. Breast cancer is often mixed.

Q: A rapid increase in the size of an osteochondroma might occur when?

Malignant transformation. **Explanation:** **Osteochondroma** (Exostosis) is the most common benign bone tumor. It is characterized by a cartilage-capped bony outgrowth from the metaphysis. While usually asymptomatic, a **rapid increase in size** after skeletal maturity is a classic "red flag" for **Malignant Transformation** into a Chondrosarcoma (occurring in <1% of solitary cases and ~5-10% of Multiple Hereditary Exostoses). **Why the other options are incorrect:** * **Bursitis:** While an overlying bursa (exostosis bursata) can form and cause swelling due to friction against soft tissues, it typically presents as a fluctuant, painful mass rather than a rapid growth of the bony lesion itself. * **Rupture of the stalk:** This is a traumatic event (fracture of the pedicle) that leads to acute pain and displacement, not a progressive increase in size. * **Dystrophic calcification:** This refers to the deposition of calcium in dead or degenerate tissue. While it may change the radiological density of the cartilage cap, it does not cause a rapid clinical increase in the tumor's dimensions. **NEET-PG High-Yield Pearls:** 1. **Cartilage Cap Thickness:** In adults, a cartilage cap **>2 cm** on MRI is highly suggestive of malignancy. 2. **Growth Plate:** Osteochondromas typically stop growing once the nearest epiphyseal plate closes. Growth in an adult is suspicious. 3. **Genetics:** Associated with mutations in **EXT1** and **EXT2** genes. 4. **Direction of Growth:** The tumor always grows **away from the joint** (towards the diaphysis).

Q: Which one of the following is a rare site for metastasis?

Forearm and leg bones. **Explanation:** The distribution of skeletal metastasis is primarily determined by the presence of **red bone marrow**. Metastatic cells typically travel via the bloodstream and settle in areas with high vascularity and active marrow. **1. Why "Forearm and leg bones" is the correct answer:** In adults, red marrow is replaced by yellow (fatty) marrow in the distal parts of the appendicular skeleton. Therefore, metastasis is **rarely seen distal to the elbow and the knee**. When metastasis does occur in the hands or feet (acrometastasis), it is most commonly associated with primary bronchogenic carcinoma. **2. Analysis of incorrect options:** * **A. Vertebrae:** This is the **most common site** for skeletal metastasis due to the extensive axial red marrow and the **Batson’s venous plexus**, which allows retrograde spread from pelvic and abdominal organs without passing through the lungs. * **B. Skull:** A frequent site for metastasis, particularly from breast, lung, and thyroid cancers. In children, Neuroblastoma often metastasizes here. * **C. Pelvis:** Along with the spine and ribs, the pelvis contains significant amounts of hematopoietically active red marrow, making it a high-predilection site. **Clinical Pearls for NEET-PG:** * **Most common primary source:** Prostate (in men) and Breast (in women). * **Most common site of metastasis:** Spine (Thoracic > Lumbar > Cervical). * **Osteoblastic lesions:** Classically seen in Prostate cancer. * **Osteolytic lesions:** Classically seen in Lung, Thyroid, and Kidney (RCC) cancers. * **Investigation of choice:** **PET-CT** or **Bone Scan** (Technetium-99m), except for Multiple Myeloma where bone scans are often negative.

Q: Which of the following statements is TRUE regarding parosteal osteosarcoma?

It may involve the medullary cavity.. **Explanation:** **Parosteal Osteosarcoma** is a subtype of surface osteosarcoma that arises from the outer layer of the periosteum. It is a **low-grade, slow-growing** malignancy, which distinguishes it from the highly aggressive conventional (medullary) osteosarcoma. 1. **Why Option C is Correct:** While parosteal osteosarcoma primarily grows on the bone surface (juxtacortical), it is a misconception that it is strictly limited to the surface. In approximately **20-25% of cases**, the tumor can erode the underlying cortex and **involve the medullary cavity**. Identifying medullary involvement is crucial for surgical planning (wide resection). 2. **Why Other Options are Incorrect:** * **Option A:** Parosteal osteosarcoma has a **significantly better prognosis** (5-year survival >90%) compared to medullary osteosarcoma, due to its low-grade nature and lower metastatic potential. * **Option B:** As explained above, medullary involvement is possible and documented in advanced stages. * **Option D:** Unlike most primary bone tumors, parosteal osteosarcoma shows a **female predilection** (F:M ratio approx. 3:2). **High-Yield Clinical Pearls for NEET-PG:** * **Most Common Site:** Posterior aspect of the **distal femur** (popliteal fossa). * **Age Group:** Older than conventional osteosarcoma (typically 20–40 years). * **Radiological Feature:** A "stuck-on" cauliflower-like ossified mass with a **radiolucent "string sign"** (a thin line separating the tumor from the cortex). * **Histology:** Shows well-differentiated osteoid with minimal atypia (often confused with Fibrous Dysplasia or Myositis Ossificans). * **Treatment:** Wide local excision is usually curative; chemotherapy is generally not required unless dedifferentiation occurs.

Q: Which tumor arises from the epiphysis?

Osteoclastoma. **Explanation:** The location of a bone tumor is a critical diagnostic clue in orthopaedics. Bone tumors are classified based on their site of origin: epiphysis, metaphysis, or diaphysis. **1. Why Osteoclastoma is correct:** **Osteoclastoma (Giant Cell Tumor/GCT)** is a benign but locally aggressive tumor that characteristically arises from the **epiphysis** after the closure of the growth plate (skeletally mature individuals, aged 20–40). It typically extends to the subchondral bone and may involve the metaphysis secondarily. On X-ray, it presents as an eccentric, "soap-bubble" appearance. **2. Why the other options are incorrect:** * **Osteochondroma:** This is the most common benign bone tumor. It arises from the **metaphysis** (specifically near the growth plate) and grows away from the joint. * **Osteoid Osteoma:** This is a small, painful benign tumor that typically occurs in the **cortex of the diaphysis** (long bones like the femur or tibia). It is characterized by a radiolucent "nidus" surrounded by sclerotic bone. * **Enchondroma:** This is a cartilage-derived tumor usually found in the **metaphysis or diaphysis** of small tubular bones (like the phalanges of the hand). **Clinical Pearls for NEET-PG:** * **Epiphyseal Tumors:** Remember the mnemonic **"GOC"** — **G**iant Cell Tumor (Adults) and **O**steo**c**hondroma (Children/Adolescents - specifically Chondroblastoma). * **Metaphyseal Tumors:** Most common site for primary bone tumors (Osteosarcoma, Ewing’s, Osteochondroma). * **Diaphyseal Tumors:** Ewing’s Sarcoma, Osteoid Osteoma, Adamantinoma, and Multiple Myeloma. * **GCT Key Fact:** It is the only tumor that is "eccentric" in location and occurs after epiphyseal fusion.

Q: What is the peak incidence decade for Ewing's sarcoma?

Second decade. **Explanation:** **Ewing’s Sarcoma** is the second most common primary malignant bone tumor in children and adolescents (after osteosarcoma). The correct answer is the **second decade** (10–20 years), which accounts for nearly 80% of cases. 1. **Why the Second Decade is Correct:** Ewing’s sarcoma is a primitive neuroectodermal tumor (PNET) characterized by the **t(11;22)** translocation. It typically arises in the **diaphysis** of long bones (like the femur) or flat bones (like the pelvis). The peak incidence occurs during the adolescent growth spurt, specifically between ages 10 and 15. 2. **Why Other Options are Incorrect:** * **First Decade:** While it can occur in children under 10, it is less common than in the teenage years. * **Third/Fourth Decade:** Ewing’s sarcoma is rare after age 30. Tumors appearing in these decades are more likely to be Giant Cell Tumors (20–40 years) or secondary malignancies. **High-Yield Clinical Pearls for NEET-PG:** * **Radiology:** Classic **"Onion-skin"** periosteal reaction due to layers of new bone formation. * **Histology:** Characterized by **Small Round Blue Cells** that are **PAS positive** (due to cytoplasmic glycogen). * **Marker:** **CD99** (MIC-2) is a highly sensitive membrane marker. * **Clinical Presentation:** Often mimics **osteomyelitis** with symptoms of pain, swelling, fever, and elevated ESR. * **Genetics:** 90% of cases show **t(11;22)(q24;q12)** translocation, resulting in the EWS-FLI1 fusion gene.

Question 1

Which of the following is NOT a diaphyseal tumor?

Accepted Answer

Chondroblastoma

Answer

Adamantinoma

Answer

Osteoid osteoma

Answer

Ewing's sarcoma

Question 2

What is the most common primary site for a metastatic bone tumor in males?

Accepted Answer

Lung

Answer

Liver

Answer

Prostate

Answer

Kidney

Question 3

Ollier's disease of bone involves which of the following?

Accepted Answer

Multiple enchondromatosis

Answer

Osteochondromatosis

Answer

Metaphyseal dysplasia

Answer

Osteoporosis

Question 4

A 40-year-old female presented with an epiphyseal tumor at the lower end of the radius. What is the most likely diagnosis?

Accepted Answer

Giant cell tumor

Answer

Ewing's sarcoma

Answer

Osteogenic sarcoma

Answer

Chondromyxoid fibroma

Question 5

Which among the following is the most common malignancy of bone?

Accepted Answer

Secondary deposits

Answer

Multiple myeloma

Answer

Osteosarcoma

Answer

Osteoid osteoma

Question 6

A rapid increase in the size of an osteochondroma might occur when?

Accepted Answer

Malignant transformation

Answer

Bursitis

Answer

Rupture of the stalk

Answer

Dystrophic calcification

Question 7

Which one of the following is a rare site for metastasis?

Accepted Answer

Forearm and leg bones

Answer

Vertebrae

Answer

Skull

Answer

Pelvis

Question 8

Which of the following statements is TRUE regarding parosteal osteosarcoma?

Accepted Answer

It may involve the medullary cavity.

Answer

It has the same prognosis as medullary osteosarcoma.

Answer

It never involves the medullary cavity.

Answer

It is more common in males compared to females.

Question 9

Which tumor arises from the epiphysis?

Accepted Answer

Osteoclastoma

Answer

Osteochondroma

Answer

Osteoid osteoma

Answer

Enchondroma

Question 10

What is the peak incidence decade for Ewing's sarcoma?

Accepted Answer

Second decade

Answer

First decade

Answer

Third decade

Answer

Fourth decade

Bone Tumors — MCQs

Bone Tumors — MCQs

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