Bone Tumors Practice Questions

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: An osteolytic mass over the iliac bone showing mottled popcorn calcifications in a 45-year-old male suggests which of the following?

Chondrosarcoma. ### Explanation **Correct Answer: B. Chondrosarcoma** The hallmark of this case is the description of **"popcorn calcifications"** within an osteolytic mass. In musculoskeletal radiology, this pattern represents **chondroid matrix mineralization**. When cartilage undergoes calcification, it forms characteristic rings, arcs, or stippled "popcorn-like" densities. **Chondrosarcoma** is a malignant cartilaginous tumor typically seen in adults aged 40–60 (matching the 45-year-old patient). It frequently involves the axial skeleton, particularly the **pelvis (iliac bone)** and proximal femur. The presence of an aggressive osteolytic lesion with chondroid matrix in an adult is highly suggestive of Chondrosarcoma. **Why the other options are incorrect:** * **A. Osteosarcoma:** Typically presents in a younger age group (bimodal, but primarily adolescents). Radiologically, it shows **osteoid matrix** (cloud-like "ivory" bone formation) rather than popcorn calcification, often accompanied by a Sunburst periosteal reaction or Codman’s triangle. * **C. Metastasis:** While common in the iliac bone of a 45-year-old, metastases are usually purely lytic or blastic. They do not produce a cartilaginous (popcorn) matrix. * **D. Osteoclastoma (Giant Cell Tumor):** This is a "soap-bubble" lytic lesion typically located in the **epiphysis** of long bones (e.g., distal femur). It does not show internal calcification or matrix formation. **High-Yield Clinical Pearls for NEET-PG:** * **Popcorn Calcification:** Pathognomonic for cartilaginous lesions (Chondroma, Enchondroma, Chondrosarcoma). * **Rings and Arcs:** Another term used to describe the calcification pattern in chondroid tumors. * **Location:** The pelvis is the most common site for primary Chondrosarcoma. * **Management:** Chondrosarcomas are notoriously resistant to chemotherapy and radiotherapy; **wide surgical excision** is the treatment of choice.

Q: Lateral X-ray of a left knee of an adolescent male is shown. What is the most probable diagnosis for this patient?

Chondromyxoid fibroma. ***Chondromyxoid fibroma*** - **Eccentric metaphyseal location** with **sclerotic margins** in the **proximal tibia** of an adolescent is classic for chondromyxoid fibroma. - This **benign cartilaginous tumor** typically presents as a **well-defined lytic lesion** with rim sclerosis in the metaphysis of long bones. *Osteosarcoma* - Would show **aggressive features** like **sunburst pattern**, **Codman triangle**, and **soft tissue mass** on X-ray. - Typically presents as a **sclerotic or mixed lesion** rather than a purely lytic lesion with sclerotic margins. *Bone cyst with fracture* - Simple bone cysts are **centrally located** in the metaphysis and show the **fallen fragment sign** when fractured. - Lacks the **eccentric location** and **sclerotic rim** characteristic of chondromyxoid fibroma. *Osteitis Fibrosis cystica* - Associated with **hyperparathyroidism** and presents as **brown tumors** with **subperiosteal bone resorption**. - Would show evidence of **generalized bone disease** and **metabolic bone changes** throughout the skeleton.

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.

Q: All of the following are true about Ewing's sarcoma except:

Low grade tumors have a good prognosis.. **Explanation:** Ewing’s sarcoma is a highly aggressive, small round blue cell tumor. The correct answer is **Option A** because the statement is factually incorrect: **Ewing’s sarcoma is always considered a high-grade malignancy.** There is no "low-grade" variant of this tumor. All cases are treated with an intensive multimodal approach (chemotherapy, surgery, and/or radiotherapy) because of its high potential for early metastasis. **Analysis of other options:** * **Option B (Pain):** Pain is indeed the most common presenting symptom, often accompanied by local swelling. It may mimic osteomyelitis due to associated systemic features like fever and elevated ESR. * **Option C (Onion peel appearance):** This is the classic radiological hallmark. It represents a **lamellated periosteal reaction** caused by the tumor pushing the periosteum away from the bone in successive layers. * **Option D (t(11;22) translocation):** This is the characteristic genetic marker found in approximately 85-90% of cases. It results in the fusion of the *EWS* gene on chromosome 22 to the *FLI1* gene on chromosome 11. **High-Yield Clinical Pearls for NEET-PG:** * **Origin:** Derived from neuroectodermal cells (PAS positive due to cytoplasmic glycogen). * **Location:** Most commonly affects the **diaphysis** (shaft) of long bones (Femur > Tibia > Humerus). * **Age Group:** Typically occurs in the first and second decades of life (5–20 years). * **Histo-pathology:** Characterized by **Homer-Wright rosettes**. * **Prognosis:** The most important prognostic factor is the presence of metastasis at the time of diagnosis (Lung is the most common site of metastasis).

Q: A 15-year-old school-going student complains of moderate occasional pain and swelling over the right knee joint. An X-ray shows a lesion in the right distal femoral epiphysis. What is the likely diagnosis?

Chondroblastoma. **Explanation:** The diagnosis of bone tumors in NEET-PG often hinges on three key factors: **Age, Location, and Radiographic appearance.** **Why Chondroblastoma is correct:** Chondroblastoma is a rare, benign bone tumor that characteristically occurs in the **epiphysis** of long bones. It typically affects adolescents (10–20 years), matching the patient’s age (15 years). The distal femur is the most common site. On X-ray, it appears as a well-defined lytic lesion with a thin sclerotic rim, sometimes showing "fluffy" calcifications (Codman’s triangle is rare here, but "chicken-wire" calcification is a classic histological finding). **Why other options are incorrect:** * **Enchondroma:** These are most commonly found in the **small bones of the hands and feet** (metaphysis/diaphysis). While they are cartilaginous, they do not typically present in the epiphysis of the femur in a teenager. * **Osteochondroma:** This is the most common benign bone tumor. It presents as a bony outgrowth (exostosis) away from the joint, usually at the **metaphysis**, not as an intra-epiphyseal lesion. * **Osteoclastoma (Giant Cell Tumor):** While GCT is also epiphyseal (or rather, subchondral/metaphyseal-epiphyseal), it typically occurs in **skeletally mature** individuals (20–40 years) after the growth plate has closed. A 15-year-old is more likely to have a Chondroblastoma. **High-Yield Clinical Pearls for NEET-PG:** * **Epiphyseal Tumors:** Remember the mnemonic **"CEO"** (Chondroblastoma, Enchondroma—rarely, Osteoclastoma). * **Chondroblastoma Histology:** Look for "Chicken-wire calcification" and "Cobblestone appearance." * **GCT (Osteoclastoma):** Look for "Soap-bubble appearance" on X-ray and "Double bubble sign." * **Osteoid Osteoma:** Pain relieved by Aspirin/NSAIDs; shows a central "nidus."

Q: What condition is characterized by the presence of a nidus?

Osteoid osteoma. **Explanation:** **Osteoid Osteoma** is the correct answer because the **nidus** is its pathognomonic radiological and histological feature. A nidus is a small, well-demarcated core of osteoid tissue (usually <1.5–2 cm) surrounded by a zone of reactive sclerotic bone. It produces high levels of prostaglandins, which explains the classic clinical presentation of severe nocturnal pain that is characteristically relieved by Aspirin or NSAIDs. **Why the other options are incorrect:** * **Osteosarcoma:** Characterized by the production of malignant osteoid by spindle cells. Key radiological features include the "Sunburst appearance" and "Codman’s triangle." * **Ewing's Sarcoma:** A small round blue cell tumor characterized by an "Onion-skin" periosteal reaction and the t(11;22) translocation. * **Chondroblastoma:** An epiphyseal tumor in young patients. Its hallmark histological feature is the "Chicken-wire" pattern of calcification, not a nidus. **High-Yield Clinical Pearls for NEET-PG:** * **Location:** Most common in the femur and tibia (cortex of long bones). * **Imaging:** CT scan is the investigation of choice to visualize the nidus. On MRI, the extensive perifocal edema can sometimes lead to a misdiagnosis of a more aggressive lesion. * **Treatment:** Medical management with NSAIDs is the first line; if refractory, **Radiofrequency Ablation (RFA)** is the gold standard treatment. * **Note:** If the nidus is >2 cm, the diagnosis shifts to **Osteoblastoma**, which typically involves the posterior elements of the spine and is not relieved by aspirin.

Q: A 20-year-old patient presents with a sclerotic lesion at the diaphysis. What is the most likely diagnosis?

Osteoid osteoma. ### Explanation **Correct Answer: C. Osteoid Osteoma** The diagnosis of **Osteoid Osteoma** is based on the patient's age and the characteristic radiological appearance. It typically affects adolescents and young adults (10–25 years). Radiologically, it presents as a small radiolucent **nidus** (less than 2 cm) surrounded by a significant zone of reactive **perifocal sclerosis**. While it can occur in the metaphysis, it is one of the classic tumors found in the **diaphysis** of long bones (especially the femur and tibia). **Why other options are incorrect:** * **Osteosarcoma:** Typically occurs in the **metaphysis** (the site of maximum growth). While it can show sclerosis, it usually presents with a "sunburst" periosteal reaction and Codman’s triangle, rather than a localized sclerotic diaphyseal lesion. * **Ewing’s Sarcoma:** Although it is a **diaphyseal** tumor in young patients, it is characterized by an aggressive "onion-skin" periosteal reaction and a large soft tissue component, rather than a purely sclerotic lesion. * **Osteochondroma:** This is a benign outgrowth (exostosis) usually found at the **metaphysis**. It grows away from the joint and is characterized by a cartilage cap, not a sclerotic diaphyseal lesion. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Symptom:** Severe nocturnal pain that is characteristically **relieved by NSAIDs/Aspirin** (due to high prostaglandin levels in the nidus). * **Common Sites:** Proximal femur (most common), followed by the tibia and spine (posterior elements). * **Radiology:** If the nidus is >2 cm, the diagnosis shifts to **Osteoblastoma**. * **Treatment:** Medical management with NSAIDs; if refractory, Radiofrequency Ablation (RFA) is the gold standard.

Question 1

Which of the following is NOT a malignant bone tumor?

Accepted Answer

Osteochondroma

Answer

Ewing's sarcoma

Answer

Chondrosarcoma

Answer

Osteosarcoma

Question 2

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 3

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 4

An osteolytic mass over the iliac bone showing mottled popcorn calcifications in a 45-year-old male suggests which of the following?

Accepted Answer

Chondrosarcoma

Answer

Osteosarcoma

Answer

Metastasis

Answer

Osteoclastoma

Question 5

Lateral X-ray of a left knee of an adolescent male is shown. What is the most probable diagnosis for this patient?

Accepted Answer

Chondromyxoid fibroma

Answer

Osteosarcoma

Answer

Bone cyst with fracture

Answer

Osteitis Fibrosis cystica

Question 6

Which tumor is most sensitive to radiotherapy?

Accepted Answer

Ewing's sarcoma

Answer

Osteogenic sarcoma

Answer

Multiple myeloma

Answer

Osteoclastoma

Question 7

All of the following are true about Ewing's sarcoma except:

Accepted Answer

Low grade tumors have a good prognosis.

Answer

Pain is the most common symptom.

Answer

Onion peel appearance on imaging.

Answer

Associated with t(11;22) translocation.

Question 8

A 15-year-old school-going student complains of moderate occasional pain and swelling over the right knee joint. An X-ray shows a lesion in the right distal femoral epiphysis. What is the likely diagnosis?

Accepted Answer

Chondroblastoma

Answer

Enchondroma

Answer

Osteochondroma

Answer

Osteoclastoma

Question 9

What condition is characterized by the presence of a nidus?

Accepted Answer

Osteoid osteoma

Answer

Osteosarcoma

Answer

Ewing's sarcoma

Answer

Chondroblastoma

Question 10

A 20-year-old patient presents with a sclerotic lesion at the diaphysis. What is the most likely diagnosis?

Accepted Answer

Osteoid osteoma

Answer

Osteosarcoma

Answer

Ewing's sarcoma

Answer

Osteochondroma

Bone Tumors — MCQs

Bone Tumors — MCQs

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