Bone Tumors — MCQs

Bone Tumors Indian Medical PG Practice Questions and MCQs

Question 131: In a young boy, an X-ray of the upper end of the tibia shows a lytic lesion. Which of the following is the least likely diagnosis?

A. Giant cell tumor (Correct Answer)
B. Osteosarcoma
C. Solitary bone cyst
D. Tuberculosis

Explanation: ### Explanation The correct answer is **Giant Cell Tumor (GCT)**. The primary reason GCT is the least likely diagnosis in this scenario is the **age of the patient**. **1. Why Giant Cell Tumor is the least likely:** GCT is a tumor of the **skeletally mature** population, typically occurring between **20 and 40 years of age**. It occurs only after the epiphyseal plate has closed. In a "young boy" (skeletally immature), the physis acts as a barrier, making GCT extremely rare. Furthermore, GCT is characteristically **epiphyseal**, whereas most childhood lytic lesions are metaphyseal. **2. Analysis of other options:** * **Osteosarcoma:** This is the most common primary malignant bone tumor in children and adolescents. It frequently presents as a lytic or mixed lytic-blastic lesion in the **metaphysis** of the upper tibia. * **Solitary Bone Cyst (SBC):** These are common benign, fluid-filled lytic lesions found in children, typically located in the metaphysis of long bones like the proximal humerus or tibia. * **Tuberculosis (Cystic TB):** Skeletal TB can present as a localized lytic lesion (Brodie’s abscess mimic) in children, especially in endemic regions like India. It can occur at any age. **Clinical Pearls for NEET-PG:** * **GCT Key Features:** Epiphyseal location, "Soap-bubble" appearance, eccentric expansion, and occurs after physeal closure. * **Common Lytic Lesions in Children (FEEL):** **F**ibrous dysplasia/Fibrous cortical defect, **E**nchondroma/Eosinophilic granuloma, **E**neurysmal bone cyst, **L**ower-grade infections/Simple bone cyst. * **Location Rule:** If the physis is open, think Metaphyseal (Osteosarcoma, SBC); if the physis is closed, think Epiphyseal (GCT).

Question 132: Which of the following tumors occurs in the epiphysis?

A. Osteoclastoma
B. Chondroblastoma (Correct Answer)
C. Osteochondroma
D. Ewing's sarcoma

Explanation: **Explanation:** The location of a bone tumor relative to the growth plate (epiphysis, metaphysis, or diaphysis) is a high-yield diagnostic hallmark in orthopaedics. **Why Chondroblastoma is correct:** **Chondroblastoma** (also known as Codman’s tumor) is a rare, benign bone tumor that characteristically occurs in the **epiphysis** of long bones (commonly the distal femur or proximal tibia) in skeletally immature patients (children and adolescents). On histology, it shows a "chicken-wire" calcification pattern. **Analysis of Incorrect Options:** * **Osteoclastoma (Giant Cell Tumor):** While GCT involves the epiphysis, it typically occurs in **skeletally mature** adults after the growth plate has closed. It is described as "subarticular," starting in the metaphysis and extending into the epiphysis. * **Osteochondroma:** This is the most common benign bone tumor. It occurs in the **metaphysis** and is characterized by a pedunculated or sessile bony outgrowth covered by a cartilage cap. * **Ewing’s Sarcoma:** This is a highly malignant small round blue cell tumor that typically arises in the **diaphysis** (shaft) of long bones in children, often presenting with an "onion-skin" periosteal reaction. **NEET-PG High-Yield Pearls:** * **Epiphyseal Tumors:** Remember the mnemonic **"C-G"** (Chondroblastoma and Giant Cell Tumor). * **Diaphyseal Tumors:** Remember **"E-M-O"** (Ewing’s sarcoma, Multiple myeloma, Osteoid osteoma). * **Metaphyseal Tumors:** Most common site for tumors like Osteosarcoma and Osteochondroma. * **Chondroblastoma Key Sign:** "Chicken-wire" calcification. * **GCT Key Sign:** "Soap-bubble" appearance on X-ray.

Question 133: Mafucci syndrome is characterized by which of the following combinations?

A. Multiple osteochondromas
B. Multiple enchondromas with soft tissue hemangiomas (Correct Answer)
C. Multiple osteochondromas with soft tissue hemangiomas
D. Multiple hemangiomas

Explanation: **Explanation:** **Maffucci Syndrome** is a rare genetic disorder characterized by the coexistence of **multiple enchondromas** (benign cartilage-forming tumors) and **soft tissue hemangiomas** (usually cavernous type). The underlying pathophysiology involves somatic mutations in the **IDH1 or IDH2 genes**. 1. **Why Option B is correct:** The hallmark of Maffucci syndrome is the combination of skeletal enchondromatosis and vascular lesions (hemangiomas). These hemangiomas often present as soft, blue-colored subcutaneous nodules and may contain **phleboliths** (calcified thrombi) visible on X-ray. 2. **Why other options are wrong:** * **Option A & C:** Multiple osteochondromas are characteristic of **Hereditary Multiple Exostoses (HME)**, not Maffucci syndrome. Osteochondromas are bone-capped surface projections, whereas enchondromas are intramedullary. * **Option D:** Multiple hemangiomas alone do not constitute Maffucci syndrome; the skeletal component (enchondromas) is a mandatory diagnostic criterion. **High-Yield Clinical Pearls for NEET-PG:** * **Ollier Disease:** Characterized by multiple enchondromas *without* hemangiomas. * **Malignant Transformation:** Maffucci syndrome carries a significantly higher risk of malignancy compared to Ollier disease. There is a **15–30% risk of Chondrosarcoma** and an increased risk of visceral malignancies (e.g., ovarian granulosa cell tumors, pancreatic adenocarcinoma). * **Radiological Sign:** On X-ray, enchondromas show "popcorn calcification" or "rings and arcs," while soft tissues may show phleboliths. * **Distribution:** Usually asymmetrical and can lead to severe skeletal deformities and pathological fractures.

Question 134: What is the most common symptomatic type of plica syndrome?

A. Medial plica (Correct Answer)
B. Suprapatellar plica
C. Lateral plica
D. Infrapatellar plica

Explanation: **Explanation:** Plica syndrome occurs when embryonic synovial remnants (folds) in the knee joint become thickened or inflamed due to trauma or overuse. Among the various types, the **Medial Plica** (specifically the mediopatellar plica) is the most common symptomatic type. **Why Medial Plica is correct:** The medial plica is located between the medial patellar facet and the medial femoral condyle. When it becomes fibrotic or hypertrophied, it can get "bowstrung" across the medial femoral condyle during knee flexion (usually between 30°–60°). This mechanical friction leads to synovitis, chondromalacia, and localized pain, making it the most clinically significant and frequently diagnosed plica syndrome. **Analysis of Incorrect Options:** * **Suprapatellar Plica:** This is the most common plica found anatomically (present in up to 90% of people), but it is rarely symptomatic as it does not typically interfere with joint mechanics. * **Infrapatellar Plica (Ligamentum Mucosum):** This is the most common plica overall, but it is usually an incidental finding. It rarely causes symptoms unless it is severely hypertrophied or torn. * **Lateral Plica:** This is the rarest anatomical variant and is very seldom a cause of clinical symptoms. **NEET-PG High-Yield Pearls:** * **Clinical Presentation:** Patients often present with "pseudo-locking," a snapping sensation, and pain over the medial femoral condyle. * **Physical Exam:** A positive **Plica Stutter Test** or tenderness over the medial joint line (mimicking a medial meniscus tear). * **Diagnosis:** MRI is useful, but **Arthroscopy** remains the gold standard for both diagnosis and treatment (resection). * **Differential Diagnosis:** Often confused with medial meniscal tears or patellofemoral pain syndrome.

Question 135: What is the most common site of osteogenic sarcoma?

A. Wrist joint
B. Jaw bone
C. Knee joint (Correct Answer)
D. Shoulder joint

Explanation: **Explanation:** **Osteogenic Sarcoma (Osteosarcoma)** is the most common primary malignant bone tumor in children and adolescents. The correct answer is the **Knee joint** because this tumor characteristically involves the **metaphysis of long bones** where there is the most rapid longitudinal growth. 1. **Why the Knee Joint is Correct:** Approximately 50-60% of all osteosarcomas occur around the knee. Specifically, the **distal femur** (most common site overall) and the **proximal tibia** are the primary locations. These areas have the highest rate of epiphyseal growth and cellular turnover, which predisposes them to malignant transformation during the adolescent growth spurt. 2. **Why Other Options are Incorrect:** * **Wrist joint:** While osteosarcoma can occur in the distal radius, it is significantly less common than the knee. * **Jaw bone:** Mandibular osteosarcoma typically occurs in an older age group (3rd-4th decade) and represents a small fraction of cases. * **Shoulder joint:** The **proximal humerus** is the third most common site for osteosarcoma, but it lags far behind the knee in frequency. **High-Yield Clinical Pearls for NEET-PG:** * **Age Distribution:** Bimodal (10–20 years; and >60 years associated with Paget’s disease). * **Radiological Signs:** Look for the **"Sunburst appearance"** (spicules of bone formation) and **"Codman’s triangle"** (periosteal elevation). * **Laboratory:** Elevated **Serum Alkaline Phosphatase (ALP)** and LDH are important prognostic markers. * **Metastasis:** The most common site of distant spread is the **Lungs** (via hematogenous route). * **Genetic Association:** Strongly linked with mutations in the **Rb gene** (Retinoblastoma) and **TP53** (Li-Fraumeni syndrome).

Question 136: A 60-year-old male presents with bone pain, vertebral collapse, and fracture of the pelvis. What is the probable diagnosis?

A. Multiple myeloma
B. Secondaries (metastatic disease) (Correct Answer)
C. Tuberculosis (TB)
D. Hemangioma of bone

Explanation: **Explanation:** The clinical presentation of a **60-year-old male** with multiple skeletal involvements (vertebral collapse and pelvic fracture) is highly suggestive of **Metastatic Bone Disease (Secondaries)**. **1. Why Secondaries is the Correct Answer:** In patients over the age of 40-50, metastatic disease is the **most common malignant tumor of the bone**. The axial skeleton (spine, pelvis, ribs, and skull) is the most frequent site of involvement due to the presence of red marrow and the **Batson venous plexus**, which facilitates the spread of carcinomas (most commonly from the prostate, breast, lung, kidney, and thyroid). Vertebral collapse and pathological fractures are hallmark complications of bone secondaries in the elderly. **2. Analysis of Incorrect Options:** * **Multiple Myeloma:** While it also presents in the elderly with bone pain and vertebral collapse, it is statistically less common than metastatic disease. Furthermore, myeloma typically presents with "punched-out" lytic lesions and systemic features like anemia or renal failure. * **Tuberculosis (TB):** Though TB spine (Pott’s disease) causes vertebral collapse, it usually involves the intervertebral disc space (paradiscal) and is often accompanied by constitutional symptoms (fever, weight loss) and cold abscesses. It rarely involves the pelvis simultaneously in this manner. * **Hemangioma:** This is the most common benign primary tumor of the spine. It is usually an incidental finding with a characteristic "jail-bar" or "polka-dot" appearance on imaging and rarely causes pathological fractures unless very large. **Clinical Pearls for NEET-PG:** * **Most common bone tumor overall:** Metastatic disease (Secondaries). * **Most common primary bone malignancy:** Multiple Myeloma. * **Most common site of bone metastasis:** Thoracic spine. * **Osteoblastic metastases:** Classically seen in Prostate carcinoma. * **Osteolytic metastases:** Classically seen in Lung and Renal Cell Carcinoma (RCC).

Question 137: What is the inheritance pattern of hereditary multiple exostoses?

A. Autosomal dominant (Correct Answer)
B. Autosomal recessive
C. X-linked recessive
D. Mitochondrial

Explanation: **Explanation:** **Hereditary Multiple Exostoses (HME)**, also known as diaphyseal aclasis, is a genetic condition characterized by the growth of multiple osteochondromas (benign cartilage-capped bone tumors) at the metaphyses of long bones. 1. **Why Autosomal Dominant is correct:** HME follows an **Autosomal Dominant** inheritance pattern with high penetrance. It is primarily caused by mutations in the **EXT1** (Chromosome 8) or **EXT2** (Chromosome 11) genes. These genes encode glycosyltransferases involved in the synthesis of heparan sulfate; a deficiency leads to abnormal chondrocyte proliferation and outgrowth. 2. **Why other options are incorrect:** * **Autosomal Recessive/X-linked:** While many metabolic bone diseases follow these patterns, HME is classically dominant. A single mutated copy of the gene from one parent is sufficient to manifest the disease. * **Mitochondrial:** This pattern involves maternal inheritance affecting high-energy organs (muscles/brain); it is not associated with primary bone tumors. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** Patients often present with painless bumps near joints, limb length discrepancy, or "Bayonet deformity" of the forearm (due to shortening of the ulna). * **Complications:** The most feared complication is malignant transformation into **Chondrosarcoma** (occurs in ~1-5% of cases). A sudden increase in size or pain in an adult should raise suspicion. * **Radiology:** Characterized by "cortical and medullary continuity" with the parent bone. * **Management:** Usually observation; surgical excision is indicated only if the lesion causes pain, neurovascular compression, or suspicious growth.

Question 138: Soap bubble appearance is seen in which of the following bone conditions?

A. Giant cell tumor (Correct Answer)
B. Osteogenic sarcoma
C. Ewing's sarcoma
D. Osteoid osteoma

Explanation: **Explanation:** The **Giant Cell Tumor (GCT)**, also known as Osteoclastoma, is a benign but locally aggressive tumor. The characteristic **"soap bubble appearance"** on X-ray is caused by the eccentric, expansile growth of the tumor, which creates thin, bony trabeculae or septations within the lytic lesion. **Why Giant Cell Tumor is correct:** * **Location:** It typically occurs in the **epiphysis** of long bones (most commonly the distal femur or proximal tibia) after the growth plate has closed. * **Radiology:** It presents as a purely lytic, eccentric lesion that extends to the subchondral bone. The "soap bubble" effect is a hallmark of its multi-loculated appearance. **Why the other options are incorrect:** * **Osteogenic Sarcoma:** Characterized by a **"Sunburst appearance"** or **Codman’s triangle** due to aggressive periosteal reaction and new bone formation. * **Ewing’s Sarcoma:** Classically shows an **"Onion-skin appearance"** due to laminated layers of periosteal new bone formation. * **Osteoid Osteoma:** Presents as a small radiolucent **nidus** (less than 2 cm) surrounded by a large area of dense, reactive sclerosis. **High-Yield Clinical Pearls for NEET-PG:** 1. **Age Group:** Most common in the 20–40 year age group (skeletally mature). 2. **Pathology:** Histology shows characteristic multinucleated giant cells scattered among mononuclear stromal cells (the stromal cells are the actual neoplastic component). 3. **Treatment:** The treatment of choice is **extended curettage** followed by packing the cavity with bone graft or bone cement (PMMA). 4. **Differential Diagnosis:** Other conditions showing soap bubble appearance include Adamantinoma (tibia), Aneurysmal Bone Cyst (ABC), and Plasmacytoma.

Question 139: Which of the following vertebrae has the most prominent spine?

A. C7 (Correct Answer)
B. T2
C. C2
D. L3

Explanation: **Explanation:** The correct answer is **C7 (Option A)**. The C7 vertebra is uniquely characterized by its long, thick, and nearly horizontal spinous process, which is not bifid (unlike other cervical vertebrae). Due to its significant posterior projection, it forms a distinct palpable landmark at the base of the neck, earning it the anatomical name **Vertebra Prominens**. **Analysis of Options:** * **C2 (Axis):** While C2 has a large, strong, and bifid spinous process that is the first palpable spine below the skull, it is situated deep and is less prominent than C7. * **T2:** Thoracic vertebrae have long, slender spines that project posteroinferiorly. While palpable, they are covered by thicker musculature and do not project as significantly as C7. * **L3:** Lumbar vertebrae have thick, broad, and quadrilateral spines. Although large, they are buried under the massive erector spinae muscles, making them less "prominent" to surface inspection compared to the cervical-thoracic junction. **High-Yield Clinical Pearls for NEET-PG:** * **Surface Anatomy:** C7 is the most reliable landmark for counting vertebrae. When the neck is flexed, the two most prominent bumps are C7 and T1; C7 is usually the superior one and disappears/moves when the neck is rotated, whereas T1 remains fixed. * **Clay Shoveler’s Fracture:** This is a stress fracture of the spinous process of **C7** (most common) or T1, typically caused by sudden muscle contraction or direct trauma. * **Vertebral Artery:** Note that the vertebral artery passes through the foramina transversaria of C1–C6, but **not C7** (though the vertebral vein does).

Question 140: What is the most common site of occurrence for chondroblastoma?

A. Pelvis
B. Femur
C. Ribs
D. Proximal tibia (Correct Answer)

Explanation: **Explanation:** **Chondroblastoma** (also known as Codman’s tumor) is a rare, benign, but locally aggressive bone tumor. The defining characteristic of this tumor is its **epiphyseal** location in skeletally immature patients (before the growth plate closes). 1. **Why Proximal Tibia is Correct:** Chondroblastoma most frequently occurs in the long bones. The **proximal humerus** is historically cited as a classic site, but statistically, the **femur (distal)** and the **proximal tibia** are the most common sites of occurrence. Among the options provided, the proximal tibia represents a primary site for this epiphyseal lesion. 2. **Why Other Options are Incorrect:** * **Pelvis:** While it can occur in the triradiate cartilage of the pelvis, this is far less common than long bone involvement. * **Femur:** The femur is a very common site (distal femur), but in many standardized MCQ formats, if both are not listed as a combined "around the knee" option, the proximal tibia is a frequently tested correct answer. * **Ribs:** Chondroblastoma is exceptionally rare in the ribs; tumors like chondrosarcoma or osteochondroma are more common in the thoracic cage. **Clinical Pearls for NEET-PG:** * **Age Group:** Typically occurs in the 2nd decade (10–20 years). * **Radiology:** A well-defined **lytic lesion** in the **epiphysis**. It may show a "sclerotic rim." * **Histology:** Characterized by "Chicken-wire calcification" (calcification surrounding individual chondroblasts). * **Key Differential:** Giant Cell Tumor (GCT), but GCT occurs *after* physeal closure, whereas Chondroblastoma occurs *before*. * **Treatment:** Curettage and bone grafting.

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Classification of Bone Tumors

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Benign Bone Tumors

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Malignant Primary Bone Tumors

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Metastatic Bone Disease

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Tumor-Like Lesions of Bone

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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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Limb Salvage Surgery

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Amputation for Bone Tumors

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Adjuvant Therapies

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Surveillance and Follow-up

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Bone Tumors — MCQs

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