Bone Tumors — MCQs

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?

Q217Medium

Which of the following is considered a precancerous lesion of bone?

Q218Easy

Which of the following is not associated with multiple myeloma?

Q219Medium

Which of the following bone tumors arise from the diaphysis?

Q220Medium

What is the radiological hallmark of Osteosarcoma?

Bone Tumors Indian Medical PG Practice Questions and MCQs

Question 211: What is the characteristic location of Ewing's sarcoma?

A. Epiphysis
B. Metaphysis
C. Diaphysis (Correct Answer)
D. Any of the above

Explanation: **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.

Question 212: Osteosarcoma originates from which type of cells?

A. Osteocytes
B. Osteoblasts (Correct Answer)
C. Chondrocytes
D. Osteoclasts

Explanation: **Explanation:** **1. Why Osteoblasts are correct:** Osteosarcoma is a primary malignant bone tumor characterized by the direct production of **osteoid** (immature bone) or bone by malignant cells. These malignant cells are mesenchymal in origin and differentiate into **osteoblasts**. Since osteoblasts are the cells responsible for bone formation, their neoplastic transformation leads to the uncontrolled production of mineralized and non-mineralized bone matrix, which is the hallmark histological feature of Osteosarcoma. **2. Why other options are incorrect:** * **Osteocytes:** These are mature bone cells trapped within the lacunae of the bone matrix. They are metabolically less active and do not typically undergo malignant transformation into Osteosarcoma. * **Chondrocytes:** These are cartilage-forming cells. Malignant transformation of these cells leads to **Chondrosarcoma**, not Osteosarcoma. * **Osteoclasts:** These are multinucleated giant cells responsible for bone resorption (derived from the monocyte-macrophage lineage). While "Giant Cell Tumors" (GCT) contain osteoclast-like cells, they are not the cell of origin for Osteosarcoma. **3. NEET-PG High-Yield Pearls:** * **Age Distribution:** Bimodal (10–20 years and >60 years associated with Paget’s disease). * **Location:** Most common site is the **metaphysis** of long bones (Distal femur > Proximal tibia). * **Radiology:** Classic findings include the **Sunburst appearance** (periosteal reaction) and **Codman’s triangle**. * **Genetic Association:** Strongly linked to mutations in the **RB1** (Retinoblastoma) and **TP53** (Li-Fraumeni syndrome) genes. * **Metastasis:** Spreads primarily via the bloodstream, most commonly to the **lungs** (skip lesions may also occur).

Question 213: What is the most common primary malignant bone tumor?

A. Osteosarcoma
B. Osteochondroma
C. Multiple myeloma (Correct Answer)
D. Osteoclastoma

Explanation: **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 214: What is the most common type of patellar bursitis?

A. Prepatellar bursitis (Correct Answer)
B. Suprapatellar bursitis
C. Infrapatellar bursitis
D. Pes anserine bursitis

Explanation: **Explanation:** **Prepatellar bursitis** is the most common type of patellar bursitis. It involves inflammation of the bursa located superficial to the patella, between the skin and the bone. This condition is classically known as **"Housemaid’s Knee"** because it is caused by repetitive friction or direct pressure from frequent kneeling. Due to its superficial location, it is highly susceptible to both chronic microtrauma and acute infection (septic bursitis). **Analysis of Incorrect Options:** * **Suprapatellar bursitis:** This involves the bursa located between the quadriceps tendon and the femur. It is actually an extension of the knee joint cavity; therefore, "bursitis" here usually manifests as a generalized knee joint effusion rather than an isolated bursal pathology. * **Infrapatellar bursitis:** This affects the bursae around the patellar ligament. **Deep infrapatellar bursitis** (between the ligament and tibia) and **superficial infrapatellar bursitis** (**"Clergyman’s Knee"**) occur less frequently than prepatellar involvement. * **Pes anserine bursitis:** Located on the medial aspect of the proximal tibia (at the insertion of Sartorius, Gracilis, and Semitendinosus), this causes medial knee pain but is anatomically distinct from the patellar bursae. **NEET-PG High-Yield Pearls:** * **Housemaid’s Knee:** Prepatellar bursitis (due to kneeling on all fours). * **Clergyman’s Knee:** Superficial infrapatellar bursitis (due to more upright kneeling/praying). * **Student’s Elbow:** Olecranon bursitis (the upper limb equivalent of prepatellar bursitis). * **Clinical Sign:** In prepatellar bursitis, the swelling is localized and superficial to the patella, and knee joint range of motion is usually preserved (unlike intra-articular effusions).

Question 215: The differential diagnosis of a lesion, histologically resembling a giant cell tumor in the small bones of the hands or feet, includes all of the following except:

A. Aneurysmal bone cyst
B. Fibrosarcoma (Correct Answer)
C. Osteosarcoma
D. Hyperparathyroidism

Explanation: **Explanation:** The core of this question lies in identifying lesions that contain **Giant Cells** on histology, which can mimic a Giant Cell Tumor (GCT). **Why Fibrosarcoma is the Correct Answer:** Fibrosarcoma is a malignant tumor of mesenchymal origin characterized by a "herringbone" pattern of spindle-shaped fibroblasts. Crucially, it **does not typically contain multinucleated giant cells** as a primary histological feature. Therefore, it is not a standard differential diagnosis for a GCT-like lesion. **Analysis of Incorrect Options (Differential Diagnoses of GCT):** * **Aneurysmal Bone Cyst (ABC):** These are common in small bones and histologically show blood-filled spaces separated by fibrous septa containing numerous multinucleated giant cells. * **Osteosarcoma:** Specifically, the **Telangiectatic variant** of osteosarcoma contains large blood-filled spaces and numerous giant cells, making it a dangerous mimic of GCT. * **Hyperparathyroidism (Brown Tumor):** This is the most classic "mimicker" of GCT. Histologically, Brown tumors are virtually indistinguishable from GCTs as they contain abundant giant cells. Clinical correlation with serum calcium and PTH levels is essential. **NEET-PG High-Yield Pearls:** 1. **GCT (Osteoclastoma):** Occurs in the **epiphysis** after skeletal maturity (20-40 years). It shows a "Soap Bubble" appearance on X-ray. 2. **Giant Cell Rich Lesions:** Remember the mnemonic **"G-A-B-O"**: **G**iant Cell Tumor, **A**neurysmal Bone Cyst, **B**rown Tumor (Hyperparathyroidism), and **O**steoblastoma/Osteosarcoma (Telangiectatic). 3. **Location:** While GCT is common in the distal femur/proximal tibia, when a "GCT-like" lesion appears in the **small bones of hands/feet**, always rule out an ABC or a Brown Tumor first.

Question 216: 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?

A. An episode of trauma often precedes the development of Ewing's sarcoma. (Correct Answer)
B. Trauma is the main etiology in the development of Ewing's sarcoma.
C. A relationship between trauma and Ewing's sarcoma has never been reported.
D. Trauma can be considered as an etiology for Ewing's sarcoma provided there is secondary infection.

Explanation: **Explanation:** **Ewing’s Sarcoma** is a highly malignant small round cell tumor typically affecting children and adolescents. The correct answer is **Option A** because a history of minor trauma is frequently reported by patients just prior to the discovery of the tumor. However, this is a **clinical association**, not a causal one. The trauma usually draws medical attention to a pre-existing, asymptomatic swelling or causes a pathological fracture, leading to the diagnosis. **Analysis of Options:** * **Option B & D:** These are incorrect because trauma is **not the etiology** (cause) of Ewing’s sarcoma. The true etiology is genetic, specifically the **t(11;22)** chromosomal translocation involving the EWS-FLI1 fusion gene. Secondary infection is also not a requirement for this association. * **Option C:** This is incorrect because the relationship is well-documented in clinical literature; many cases are "unmasked" by an incidental traumatic event. **Clinical Pearls for NEET-PG:** * **Radiology:** Characterized by a "moth-eaten" destructive pattern and **"onion-skin"** periosteal reaction (due to layers of new bone formation). * **Clinical Mimicry:** It often presents with systemic symptoms like fever, elevated ESR, and leukocytosis, frequently mimicking **Acute Osteomyelitis**. * **Site:** Most common in the diaphysis of long bones (Femur is most common), but can occur in flat bones like the pelvis and mandible. * **Histology:** Small, round, blue cells that are **PAS positive** (due to cytoplasmic glycogen) and express **CD99 (MIC2)**.

Question 217: Which of the following is considered a precancerous lesion of bone?

A. Paget disease
B. Chronic osteomyelitis
C. Benign giant cell tumor
D. All of the above (Correct Answer)

Explanation: **Explanation:** A **precancerous (premalignant) lesion** of the bone is a benign condition or a chronic inflammatory state that carries a significantly higher risk of transforming into a malignancy, most commonly Osteosarcoma or Squamous Cell Carcinoma. * **Paget Disease (Osteitis Deformans):** In elderly patients, Paget disease is a well-known precursor to **Pagetoid Osteosarcoma**. The rapid bone turnover and hypervascularity increase the risk of malignant transformation (seen in ~1% of cases). * **Chronic Osteomyelitis:** Long-standing infection with a persistent discharging sinus can lead to malignant transformation of the skin/tract epithelium into **Squamous Cell Carcinoma** (Marjolin’s ulcer). Rarely, it can also lead to Osteosarcoma or Fibrosarcoma. * **Benign Giant Cell Tumor (GCT):** While primarily benign, GCT is "locally aggressive." It can undergo malignant transformation (Secondary Malignant GCT), especially following radiotherapy, or rarely, it can metastasize to the lungs even in its benign histological form. **High-Yield Clinical Pearls for NEET-PG:** * **Most common malignancy in Paget disease:** Osteosarcoma. * **Marjolin’s Ulcer:** A squamous cell carcinoma arising in a chronic burn scar or a chronic osteomyelitis sinus tract. * **Other Precancerous Lesions:** Enchondroma (especially in Ollier disease/Maffucci syndrome), Osteochondroma (especially in Multiple Exostoses), and Fibrous Dysplasia (McCune-Albright syndrome). * **Radiation:** Previous exposure to therapeutic radiation is a major risk factor for secondary bone sarcomas.

Question 218: Which of the following is not associated with multiple myeloma?

A. Bone pain
B. Metastatic calcification
C. Punched out lesion in the skull
D. Carpopedal spasm (Correct Answer)

Explanation: ### Explanation **Multiple Myeloma (MM)** is a plasma cell dyscrasia characterized by the neoplastic proliferation of a single clone of plasma cells. The hallmark of the disease is increased osteoclastic activity, which leads to significant bone destruction. **Why Carpopedal Spasm is the Correct Answer:** Carpopedal spasm is a clinical sign of **hypocalcemia** (low serum calcium). In Multiple Myeloma, the extensive bone destruction mediated by Osteoclast Activating Factors (OAFs) like IL-6 and RANKL leads to **hypercalcemia**, not hypocalcemia. Therefore, carpopedal spasm is not associated with MM; instead, patients may present with symptoms of "stones, bones, abdominal groans, and psychic overtones" due to high calcium levels. **Analysis of Incorrect Options:** * **Bone Pain:** This is the most common presenting symptom of MM. It results from lytic lesions, pathologic fractures, and cortical thinning, typically involving the spine and ribs. * **Metastatic Calcification:** Due to chronic hypercalcemia and potential renal failure, calcium deposits can occur in normal tissues such as the kidneys (nephrocalcinosis), lungs, and gastric mucosa. * **Punched-out Lesions:** These are the classic radiographic hallmark of MM. They appear as sharply defined, "cookie-cutter" lytic areas without a sclerotic rim, most characteristically seen on a lateral skull X-ray. **High-Yield Clinical Pearls for NEET-PG:** * **CRAB Criteria:** **C**alcium (elevated), **R**enal insufficiency, **A**nemia, **B**one lesions. * **Bence-Jones Proteins:** Light chains found in urine; they do not show up on a standard dipstick (requires sulfosalicylic acid test). * **Diagnosis:** Bone marrow biopsy showing >10% plasma cells is a major diagnostic criterion. * **M-Spike:** Found on Serum Protein Electrophoresis (SPEP), usually IgG or IgA. * **Cold Bone Scan:** MM lesions are often "cold" on Technetium-99m bone scans because there is little to no osteoblastic activity; X-rays (Skeletal Survey) are the preferred initial imaging.

Question 219: Which of the following bone tumors arise from the diaphysis?

A. Chondrosarcoma
B. Ewing's tumor
C. Osteoclastoma
D. Osteoid osteoma (Correct Answer)

Explanation: **Explanation:** The location of a bone tumor relative to the growth plate (Epiphysis, Metaphysis, or Diaphysis) is a high-yield diagnostic marker in orthopaedics. **Why Osteoid Osteoma is Correct:** **Osteoid osteoma** is a benign, bone-forming tumor that typically arises in the **diaphysis** (shaft) of long bones, most commonly the femur and tibia. It is characterized by a small radiolucent "nidus" (less than 2 cm) surrounded by significant reactive sclerosis. Its classic clinical presentation is nocturnal pain that is dramatically relieved by Aspirin or NSAIDs. **Analysis of Incorrect Options:** * **A. Chondrosarcoma:** This is a malignant cartilage-forming tumor. While it can occur in various locations, it most commonly arises in the **metaphysis** or the flat bones (pelvis, ribs). * **B. Ewing’s Tumor:** This is a classic **diaphyseal** tumor. However, in the context of this specific question (where Osteoid Osteoma is marked correct), it is important to note that while Ewing’s is the most common *malignant* diaphyseal tumor, Osteoid Osteoma is a primary *benign* diaphyseal tumor. (Note: In many exams, both are considered diaphyseal; always check for the "most correct" or specific clinical context provided). * **C. Osteoclastoma (Giant Cell Tumor):** This is the classic **epiphyseal** tumor (occurring after the growth plate closes). It is known for its "soap bubble" appearance on X-ray. **NEET-PG High-Yield Pearls:** * **Diaphyseal Tumors:** Remember the mnemonic **"EOMS"** — **E**wing’s sarcoma, **O**steoid osteoma, **M**yeloma, and **S**teatocystoma (or Adamantinoma/Eosinophilic Granuloma). * **Epiphyseal Tumors:** Giant Cell Tumor (GCT) and Chondroblastoma (the only one occurring before physis closure). * **Metaphyseal Tumors:** Most common site for Osteosarcoma, Osteochondroma, and Enchondroma. * **Osteoid Osteoma vs. Osteoblastoma:** If the nidus is >2 cm, it is classified as an Osteoblastoma (often involves the posterior elements of the spine).

Question 220: What is the radiological hallmark of Osteosarcoma?

A. Soap bubble appearance
B. Sun ray appearance (Correct Answer)
C. Osteoid formation by neoplastic cells
D. Cotton wool appearance

Explanation: ### Explanation **Correct Option: B. Sun ray appearance** Osteosarcoma is a highly aggressive malignant bone tumor characterized by rapid growth. As the tumor expands, it lifts the periosteum away from the bone cortex. The malignant cells stimulate the formation of new bone along the stretched perforating fibers (Sharpey’s fibers) perpendicular to the bone surface. This creates a radiating, spiculated pattern of calcification known as the **"Sun ray" or "Sunburst" appearance**. **Analysis of Incorrect Options:** * **A. Soap bubble appearance:** This is the hallmark of **Giant Cell Tumor (Osteoclastoma)**, typically seen in the epiphysis of long bones. It can also be seen in Adamantinoma. * **C. Osteoid formation by neoplastic cells:** While this is the **pathological/histological hallmark** of Osteosarcoma, the question specifically asks for the **radiological** hallmark. * **D. Cotton wool appearance:** This is characteristic of **Paget’s disease of the bone** (specifically in the skull), representing thickened, disorganized sclerotic patches. **NEET-PG High-Yield Pearls:** 1. **Codman’s Triangle:** Another classic radiological sign of Osteosarcoma, formed when the tumor elevates the periosteum, creating a triangular area of new subperiosteal bone at the tumor margin. 2. **Location:** Most common site is the **metaphysis** of long bones, particularly around the knee (distal femur/proximal tibia). 3. **Age Group:** It shows a bimodal distribution, primarily affecting adolescents (10–20 years) and elderly patients with pre-existing Paget’s disease. 4. **Metastasis:** The most common site of distant spread is the **lungs** (via hematogenous route).

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Soft Tissue Tumors

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Evaluation and Staging of Bone Tumors

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Biopsy Principles

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Bone Tumors — MCQs

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