Bone Tumors Practice Questions

Q: Which bone tumor commonly arises from the metaphysis?

Osteogenic sarcoma. **Explanation:** The location of a bone tumor is a critical diagnostic clue in orthopaedics. Bone tumors are typically classified based on their site of origin: **Epiphysis, Metaphysis, or Diaphysis.** **1. Why Osteogenic Sarcoma (Osteosarcoma) is correct:** Osteosarcoma is the most common primary malignant bone tumor in children and adolescents. It characteristically arises in the **metaphysis** of long bones (most commonly the distal femur and proximal tibia). This is because the metaphysis is the site of most active bone turnover and growth plate activity, where mesenchymal stem cells are prone to malignant transformation. **2. Analysis of Incorrect Options:** * **Ewing Sarcoma:** This tumor typically arises from the **diaphysis** (shaft) of long bones. It is characterized by a "small round blue cell" appearance and an "onion-skin" periosteal reaction. * **Osteoclastoma (Giant Cell Tumor):** This is a classic **epiphyseal** tumor (occurring after growth plate closure). It is known for its "soap bubble" appearance on X-ray and its tendency to extend to the articular surface. * **Osteoid Osteoma:** While it can occur in the metaphysis, it is more frequently found in the **cortex of the diaphysis**. It is clinically distinguished by nocturnal pain relieved by aspirin. **NEET-PG High-Yield Pearls:** * **Metaphyseal tumors:** Osteosarcoma, Osteochondroma, Enchondroma, and Aneurysmal Bone Cyst (ABC). * **Epiphyseal tumors:** Giant Cell Tumor (GCT) and Chondroblastoma (the only one in children). * **Diaphyseal tumors:** Ewing Sarcoma, Adamantinoma, and Osteoid Osteoma. * **Radiological Sign for Osteosarcoma:** Sunburst appearance and Codman’s triangle.

Q: A radiolucent defect in bone that is a cause of a pathologic fracture and nocturnal pain in the legs in children is:

A fibrous cortical defect. **Explanation:** **Fibrous Cortical Defect (FCD)**, also known as a metaphyseal fibrous defect, is a common, benign, asymptomatic lesion found in up to 40% of healthy children. 1. **Why Option A is Correct:** FCDs are small, radiolucent, eccentric cortical lesions with a well-defined sclerotic border, typically located in the distal femur or proximal tibia. While usually asymptomatic, if the lesion grows to involve more than 50% of the bone diameter, it becomes a **Non-Ossifying Fibroma (NOF)**. Large NOFs weaken the cortex, leading to **pathologic fractures**. The mention of **nocturnal pain** in children is a classic clinical distractor; while often associated with Osteoid Osteoma, it can occur in FCD/NOF due to microfractures or rapid growth phases. 2. **Why Other Options are Incorrect:** * **B. Aneurysmal Bone Cyst (ABC):** These present as "expansile," soap-bubble, eccentric lesions. While they cause fractures, they are typically painful and aggressive, not incidental cortical defects. * **C. Fibrous Dysplasia:** Characterized by a "ground-glass" appearance and expansion of the medullary canal (not just a cortical defect). It often presents with "Shepherd’s Crook" deformity. * **D. Enchondroma:** These are central (medullary) lucent lesions, most common in the small bones of the hands/feet, often showing "stippled" calcification. **High-Yield Clinical Pearls for NEET-PG:** * **Radiology Sign:** "Jaffe-Campanacci Syndrome" involves multiple NOFs associated with café-au-lait spots and mental retardation. * **Natural History:** Most FCDs are "leave me alone" lesions that spontaneously regress and ossify by adulthood. * **Fracture Risk:** A lesion is at high risk for pathologic fracture if it exceeds **50% of the bone width** or **33% of the cortical thickness**.

Q: Vertebra plana occurs in which of the following conditions?

Eosinophilic granuloma. **Vertebra Plana** refers to the complete symmetrical collapse of a vertebral body, resulting in a thin, flat, "coin-on-edge" appearance on lateral radiographs, while the adjacent intervertebral discs remain preserved. ### **Why Eosinophilic Granuloma is Correct** **Eosinophilic Granuloma (EG)**, the localized form of Langerhans Cell Histiocytosis (LCH), is the most common cause of vertebra plana in children. The disease involves an abnormal proliferation of histiocytes which causes focal bone destruction. In the spine, this leads to a pathological fracture and rapid collapse of the vertebral body. Because the intervertebral discs are resistant to the histiocytic process, they remain intact, creating the classic radiographic appearance. ### **Why Other Options are Incorrect** * **B, C, and D (Chondrosarcoma, Osteosarcoma, Fibrosarcoma):** These are aggressive primary malignant bone tumors. While they can cause vertebral destruction and pathological fractures, they typically present with asymmetrical collapse, significant soft tissue masses, and destruction of posterior elements. They rarely result in the uniform, pancake-like flattening characteristic of vertebra plana. ### **NEET-PG High-Yield Pearls** * **Classic Sign:** "Calvé’s disease" was the historical term for vertebra plana, now known to be caused primarily by EG. * **Age Group:** Most commonly seen in children aged 2–10 years. * **Differential Diagnosis (Mnemonic: FETID):** * **F**racture (Trauma) * **E**osinophilic Granuloma (Most common) * **T**uberculosis (though TB usually destroys the disc space first) * **I**nfection/Inflammation * **D**iffuse Malignancy (Leukemia/Metastasis) * **Prognosis:** In EG, the collapsed vertebra often shows significant "re-expansion" or partial height recovery over time after the disease resolves.

Q: Which of the following is NOT a malignant bone tumor?

Osteochondroma. **Explanation:** The correct answer is **Osteochondroma** because it is a **benign** bone tumor, whereas the other options represent primary malignant bone malignancies. **1. Why Osteochondroma is the correct answer:** Osteochondroma (also known as Exostosis) is the **most common benign bone tumor**. It is a cartilage-capped bony outgrowth that typically arises from the metaphysis of long bones (most commonly around the knee). It is characterized by the fact that its marrow cavity is continuous with that of the host bone. While it has a small risk (<1%) of malignant transformation into chondrosarcoma, the lesion itself is benign. **2. Why the other options are incorrect:** * **Osteosarcoma:** The most common primary malignant bone tumor in children and adolescents. It is characterized by the production of osteoid (immature bone) by malignant cells. * **Ewing’s Sarcoma:** A highly malignant small round blue cell tumor, typically occurring in the diaphysis of long bones in children. * **Chondrosarcoma:** A malignant tumor of cartilage-producing cells, usually seen in older adults (40–60 years). **High-Yield Clinical Pearls for NEET-PG:** * **Osteochondroma:** Look for the "mushroom-shaped" appearance on X-ray and the pathognomonic feature: **cortical and medullary continuity** with the parent bone. * **Multiple Hereditary Exostoses (MHE):** An autosomal dominant condition with multiple osteochondromas; it carries a higher risk of malignancy (approx. 5-10%). * **Radiological Signs:** * Osteosarcoma: Sunburst appearance, Codman’s triangle. * Ewing’s Sarcoma: Onion-peel appearance. * Osteochondroma: Pedunculated or sessile outgrowth away from the joint.

Q: Which of the following statements are true about Eosinophilic granuloma?

Osteolytic lesion and Skull is commonly affected. **Explanation:** **Eosinophilic Granuloma (EG)** is the most common and benign manifestation of **Langerhans Cell Histiocytosis (LCH)**. It is characterized by the clonal proliferation of Langerhans cells, leading to localized bone destruction. 1. **Why Option A is Correct:** * **Osteolytic Lesion:** The hallmark of EG is a sharply defined, "punched-out" osteolytic lesion without a sclerotic rim. In the skull, this often creates a "beveled edge" appearance due to unequal involvement of the inner and outer tables. * **Site Predilection:** The **skull** is the most common site of involvement (especially the calvarium), followed by the mandible, ribs, pelvis, and femur. 2. **Why Other Options are Incorrect:** * **Gender (Options B & C):** EG shows a distinct **male predominance** (M:F ratio approx. 2:1). It is not more common in females. * **Age (Option D):** It is primarily a disease of **children and adolescents**. Most cases occur before the age of 20 (peak incidence 5–10 years). It is rare in the 20–45 age group. **High-Yield Clinical Pearls for NEET-PG:** * **Vertebra Plana:** In the spine, EG causes symmetrical collapse of the vertebral body, known as **Calvé’s disease** or "coin-on-edge" appearance. * **Floating-in-air teeth:** Mandibular involvement leads to loss of alveolar bone, making teeth appear as if they are floating. * **Histology:** Look for **Birbeck granules** (tennis-racket shaped organelles) on electron microscopy and **CD1a/S100/CD207 (Langerin)** positivity on immunohistochemistry. * **Treatment:** Small asymptomatic lesions may resolve spontaneously; symptomatic ones are treated with curettage or local steroid injection.

Q: A 50-year-old patient presents with a lesion in the midline involving the sacrum. The lesion is found to be sclerotic. What is the most probable diagnosis?

Chordoma. **Explanation:** The correct answer is **Chordoma**. **Why Chordoma is correct:** Chordomas are rare, slow-growing malignant tumors that arise from the remnants of the **notochord**. They have a strong predilection for the **midline** of the axial skeleton. The most common site is the **sacrococcygeal region (50%)**, followed by the spheno-occipital (clivus) and vertebral regions. While chordomas are typically described as osteolytic with soft tissue components, they can frequently present with **sclerotic margins** or internal calcifications (sequestra), especially in the sacral region. In a 50-year-old patient with a midline sacral lesion, Chordoma is the classic "textbook" diagnosis. **Why other options are incorrect:** * **Metastatic lesion:** While metastases are the most common bone tumors in patients over 50, they are rarely confined strictly to the midline of the sacrum and usually present with multiple lesions or a known primary (e.g., prostate, breast). * **Osteosarcoma:** This typically affects the metaphyseal ends of long bones in younger populations (bimodal distribution). Primary sacral osteosarcoma is extremely rare. * **Chondrosarcoma:** Although it can occur in the pelvis of older adults, it usually arises from the ilium or flat bones and presents with a characteristic "popcorn" calcification rather than a purely midline sacral location. **High-Yield Clinical Pearls for NEET-PG:** * **Histology:** Look for **Physaliphorous cells** (large, vacuolated cells with a "soap bubble" appearance). * **Immunohistochemistry:** Chordomas are positive for **S-100 and Brachyury** (highly specific). * **Treatment:** They are relatively radioresistant; the treatment of choice is wide local surgical excision. * **Age Group:** Most common in the 5th to 7th decades of life.

Q: In Rickets, which of the following clinical findings is NOT typically seen?

Bleeding. **Explanation:** The correct answer is **Bleeding**. Rickets is a metabolic bone disease characterized by a failure of osteoid mineralization, primarily due to Vitamin D deficiency, leading to soft and weak bones. **Bleeding** is not a feature of Rickets; rather, it is the hallmark of **Scurvy (Vitamin C deficiency)**, where defective collagen synthesis leads to capillary fragility, resulting in gingival bleeding, subperiosteal hemorrhages, and petechiae. **Analysis of Incorrect Options:** * **Bowing of legs (Genu Varum):** As the child begins to weight-bear, the softened femoral and tibial shafts succumb to mechanical stress, leading to characteristic lateral bowing. * **Rachitic Rosary:** This refers to the palpable and visible enlargement of the costochondral junctions. It is caused by the expansion of unmineralized cartilage at the growth plates of the ribs. * **Craniotabes:** This is often the earliest sign of Rickets (seen in infants <6 months). It manifests as softening of the skull bones (usually the occipital or parietal bones), which give a "ping-pong ball" sensation upon pressure. **NEET-PG High-Yield Pearls:** 1. **Radiological Hallmark:** Fraying, cupping, and splaying of the metaphysis (best seen at the distal radius and ulna). 2. **Biochemical Profile:** Low/Normal Calcium, **Low Phosphate**, and **Elevated Alkaline Phosphatase (ALP)**. ALP is the most sensitive marker for disease activity. 3. **Harrison’s Sulcus:** A horizontal groove along the lower border of the thorax corresponding to the insertion of the diaphragm. 4. **Widening of Wrist:** One of the earliest clinical signs in an older infant.

Q: Osteoblastic metastasis is typically seen in which of the following conditions?

Prostate carcinoma. **Explanation:** Bone metastases are classified based on the primary mechanism of bone remodeling disruption: **Osteoblastic** (bone-forming) or **Osteolytic** (bone-destroying). **1. Why Prostate Carcinoma is Correct:** Prostate carcinoma is the classic example of **osteoblastic metastasis**. The tumor cells secrete factors like Bone Morphogenetic Proteins (BMPs) and Endothelin-1, which stimulate osteoblast activity. On imaging, these appear as dense, white, "sclerotic" lesions. In males, prostate cancer is the most common cause of blastic lesions. **2. Why the Other Options are Incorrect:** * **Multiple Myeloma:** Characteristically produces purely **osteolytic** "punched-out" lesions. It involves RANKL-mediated osteoclast activation and inhibits osteoblasts, which is why bone scans (which depend on osteoblast activity) are often falsely negative. * **Thyroid Carcinoma:** Typically presents as **osteolytic** lesions. A high-yield feature of follicular thyroid metastasis is that the lesions are often highly vascular and "pulsatile." * **Renal Carcinoma (RCC):** Primarily causes aggressive **osteolytic** destruction. Like thyroid cancer, RCC metastases are known for being extremely vascular and can present as "blow-out" lytic lesions. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Blastic Lesions:** "**P**rostate, **B**reast (can be mixed), **S**mall cell lung cancer, **C**arcinoid, **H**odgkin’s Lymphoma" (**P**hiladelphia **B**ulletin **S**ports **C**hannel **H**eadlines). * **Mnemonic for Lytic Lesions:** "**L**ung (NSCLC), **K**idney, **T**hyroid, **G**I tract" (**L**ike **K**illing **T**he **G**iant). * **Breast Cancer:** The most common cause of **mixed** (lytic and blastic) lesions. * **Investigation of Choice:** **99mTc-MDP Bone Scan** is highly sensitive for blastic lesions but poor for Multiple Myeloma.

Q: Onion peel appearance is seen in which of the following conditions?

Ewing's sarcoma. **Explanation:** The **"Onion peel" appearance** is a classic radiological sign of **Ewing’s sarcoma**. This phenomenon occurs due to a **laminated periosteal reaction**. When the tumor grows rapidly, it pushes the periosteum away from the bone cortex. The periosteum responds by depositing multiple concentric layers of new bone, resembling the layers of an onion. **Analysis of Options:** * **Ewing’s Sarcoma (Correct):** A highly malignant small round cell tumor typically occurring in the diaphysis of long bones in children. The characteristic "onion peel" appearance is its hallmark radiological feature. * **Osteoma:** A benign, slow-growing tumor (often in the skull) characterized by dense, mature bone. It does not show periosteal reactions. * **Osteosarcoma:** Typically presents with a **"Sunburst" appearance** or **Codman’s triangle** due to rapid, aggressive bone formation and periosteal elevation. * **Osteoclastoma (Giant Cell Tumor):** Characterized by a **"Soap bubble" appearance**, usually located in the epiphysis of long bones in young adults. **High-Yield Clinical Pearls for NEET-PG:** * **Genetic Marker:** Ewing’s sarcoma is associated with the **t(11;22)** translocation (EWS-FLI1 fusion). * **Histology:** Shows **Small Round Blue Cells** and **Homer-Wright rosettes**. * **Clinical Mimic:** It often presents with fever and elevated ESR, frequently mimicking **Acute Osteomyelitis**. * **PAS Staining:** Ewing’s cells are **PAS positive** due to the presence of glycogen in the cytoplasm.

Q: Which tumor is most sensitive to radiotherapy?

Ewing's sarcoma. **Explanation:** The correct answer is **Ewing’s Sarcoma**. In musculoskeletal oncology, the sensitivity of a tumor to radiotherapy is generally determined by its cellular origin and growth rate. **1. Why Ewing’s Sarcoma is correct:** Ewing’s sarcoma is a highly malignant, small round blue cell tumor. These tumors are characterized by rapid cell division and high metabolic activity, making them extremely **radiosensitive**. While surgery remains the primary treatment for local control when feasible, radiotherapy is a cornerstone of management, especially for unresectable tumors or as an adjuvant to chemotherapy. **2. Analysis of Incorrect Options:** * **Osteogenic Sarcoma (Osteosarcoma):** This is a primary bone-forming tumor. It is notoriously **radioresistant**. Treatment relies heavily on neoadjuvant chemotherapy followed by wide local excision. * **Multiple Myeloma:** While plasma cell tumors are **radiosensitive**, Ewing’s sarcoma is traditionally considered the "most" sensitive among primary bone malignancies in a comparative clinical context. In many classifications, Ewing’s and Lymphoma are grouped as the most responsive. * **Osteoclastoma (Giant Cell Tumor):** This is a locally aggressive but usually benign tumor. Radiotherapy is generally **avoided** because it carries a high risk of inducing secondary malignant transformation (post-radiation sarcoma). **3. NEET-PG High-Yield Pearls:** * **Radiosensitivity Hierarchy:** Ewing’s Sarcoma > Multiple Myeloma > Lymphoma. * **Genetic Marker:** Ewing’s is associated with the **t(11;22)** translocation (EWS-FLI1 gene). * **Radiological Sign:** Classic "Onion-skin" periosteal reaction. * **Chemotherapy:** The standard regimen is **VAC/IE** (Vincristine, Adriamycin, Cyclophosphamide / Ifosfamide, Etoposide). * **Most Radioresistant Bone Tumor:** Osteosarcoma and Chondrosarcoma.

Question 1

Which bone tumor commonly arises from the metaphysis?

Accepted Answer

Osteogenic sarcoma

Answer

Ewing sarcoma

Answer

Osteoclastoma

Answer

Osteoid osteoma

Question 2

A radiolucent defect in bone that is a cause of a pathologic fracture and nocturnal pain in the legs in children is:

Accepted Answer

A fibrous cortical defect

Answer

An aneurysmal bone cyst

Answer

Fibrous dysplasia

Answer

An enchondroma

Question 3

Vertebra plana occurs in which of the following conditions?

Accepted Answer

Eosinophilic granuloma

Answer

Chondrosarcoma

Answer

Osteosarcoma

Answer

Fibrosarcoma

Question 4

Which of the following is NOT a malignant bone tumor?

Accepted Answer

Osteochondroma

Answer

Ewing's sarcoma

Answer

Chondrosarcoma

Answer

Osteosarcoma

Question 5

Which of the following statements are true about Eosinophilic granuloma?

Accepted Answer

Osteolytic lesion and Skull is commonly affected

Answer

More common in females and Osteolytic lesion

Answer

More common in females and Skull is commonly affected

Answer

M.C. in 20-45 years of age and Osteolytic lesion

Question 6

A 50-year-old patient presents with a lesion in the midline involving the sacrum. The lesion is found to be sclerotic. What is the most probable diagnosis?

Accepted Answer

Chordoma

Answer

Metastatic lesion

Answer

Osteosarcoma

Answer

Chondrosarcoma

Question 7

In Rickets, which of the following clinical findings is NOT typically seen?

Accepted Answer

Bleeding

Answer

Bowing of legs

Answer

Rachitic Rosary

Answer

Craniotabes

Question 8

Osteoblastic metastasis is typically seen in which of the following conditions?

Accepted Answer

Prostate carcinoma

Answer

Multiple myeloma

Answer

Thyroid carcinoma

Answer

Renal carcinoma

Question 9

Onion peel appearance is seen in which of the following conditions?

Accepted Answer

Ewing's sarcoma

Answer

Osteoma

Answer

Osteosarcoma

Answer

Osteoclastoma

Question 10

Which tumor is most sensitive to radiotherapy?

Accepted Answer

Ewing's sarcoma

Answer

Osteogenic sarcoma

Answer

Multiple myeloma

Answer

Osteoclastoma

Bone Tumors — MCQs

Bone Tumors — MCQs

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