Principles of Musculoskeletal Oncology — MCQs
Which of the following is not true about osteosarcoma?
N3a TNM staging of head and neck tumors (AJCC 8th edition) shows:
What is the most common primary bone tumor in adults?
Distant bone metastases can be best detected by which of the following imaging techniques?
Which of the following tumours is radiosensitive?
Which of the following is a bone-forming malignant tumor?
Which of the following is an epiphyseal lesion?
Which of the following are features of Gorham's disease (Disappearing Bones)?
Onion peel appearance on radiograph is not seen in which of the following conditions?
Chemotherapy of Ewing's sarcoma includes all except?
Principles of Musculoskeletal Oncology Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following is not true about osteosarcoma?
- A. Seen in the metaphyseal region of the long bones
- B. Lung metastasis is common
- C. Secondary osteosarcoma is seen in older age groups
- D. Most commonly arises in the epiphyseal region (Correct Answer)
Explanation: ***Most commonly arises in the epiphyseal region*** - This statement is **FALSE** - osteosarcoma most commonly arises in the **metaphyseal region** of long bones, particularly around the knee (distal femur, proximal tibia) and proximal humerus [1]. - The metaphysis is the region where bone growth is most active, which explains why osteosarcoma preferentially occurs there. - The epiphysis (growth plate region) is **not** the typical location for osteosarcoma. *Seen in the metaphyseal region of the long bones* - This is **TRUE** - osteosarcoma characteristically arises in the **metaphyseal regions** of long bones, especially around the knee and proximal humerus where growth is most active [1]. *Lung metastasis is common* - This is **TRUE** - the lungs are the most common site of distant metastasis in osteosarcoma, occurring in up to 80% of patients who develop metastatic disease [1]. - Pulmonary metastasis significantly impacts prognosis and treatment [1]. *Secondary osteosarcoma is seen in older age groups* - This is **TRUE** - while primary osteosarcoma affects children and young adults (peak 10-20 years), **secondary osteosarcoma** occurs in older patients, typically arising in association with Paget's disease, prior radiation therapy, or bone infarcts [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1200-1202.
Question 2: N3a TNM staging of head and neck tumors (AJCC 8th edition) shows:
- A. Metastasis in a lymph node >6 cm (Correct Answer)
- B. Metastasis in lymph nodes >2 cm
- C. Metastasis in lymph nodes >5 cm
- D. None of the options
Explanation: ***Metastasis in a lymph node >6 cm*** - **N3a disease** in head and neck cancer staging (AJCC 8th edition) specifically refers to metastasis in a single lymph node larger than 6 cm in greatest dimension **without extranodal extension (ENE)**. - This applies to oral cavity, oropharynx (HPV-negative), hypopharynx, and larynx cancers. - **Note:** N3 staging also includes **N3b** (metastasis in any node with clinically overt ENE), but this question specifically asks about N3a criteria. *Metastasis in lymph nodes >2 cm* - Lymph nodes in the 2-3 cm range typically fall within **N1 or N2a categories**, depending on laterality and number of involved nodes. - **N3a disease** requires a single lymph node to exceed 6 cm in greatest dimension without ENE. *Metastasis in lymph nodes >5 cm* - A lymph node between 3-6 cm is usually classified as **N2 disease** (N2a if single ipsilateral ≤6 cm, N2b if multiple ipsilateral ≤6 cm, N2c if bilateral or contralateral ≤6 cm). - To be classified as **N3a**, the lymph node must be **>6 cm** without extranodal extension. *None of the options* - This option is incorrect because the first option accurately describes the size criterion for **N3a TNM staging** in head and neck tumors according to AJCC 8th edition guidelines. - While N3 staging has two subcategories (N3a and N3b), the size criterion of >6 cm correctly defines N3a disease.
Question 3: What is the most common primary bone tumor in adults?
- A. Chondrosarcoma (Correct Answer)
- B. Ewing's sarcoma
- C. Adamantinoma
- D. Osteogenic sarcoma
Explanation: ***Chondrosarcoma*** - **Chondrosarcoma** is the **most common primary malignant bone tumor in adults**, typically affecting older individuals (over 40-50 years) [1]. - It arises from **cartilage-producing cells** and is characterized by the production of malignant cartilage matrix [1]. - Common sites include pelvis, femur, and shoulder girdle [2]. *Osteogenic sarcoma* - **Osteogenic sarcoma** (osteosarcoma) is the most common primary malignant bone tumor in **children and adolescents**, not adults overall [1]. - There is a second peak incidence in older adults, often associated with **Paget's disease** or prior radiation. - It arises from osteoblasts and produces immature bone (osteoid). *Adamantinoma* - **Adamantinoma** is a rare, low-grade malignant bone tumor that almost exclusively occurs in the **tibia**. - It has a characteristic biphasic histologic pattern with epithelial and osteofibrous components. *Ewing's sarcoma* - **Ewing's sarcoma** is the second most common primary malignant bone tumor in **children and young adults** (ages 5-25 years). - It is a highly aggressive tumor with specific chromosomal translocation t(11;22) and composed of **small round blue cells**. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1204. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 673-674.
Question 4: Distant bone metastases can be best detected by which of the following imaging techniques?
- A. Bone scan (Correct Answer)
- B. CT
- C. Intravenous venogram
- D. PET scan
Explanation: ***Bone scan*** - A **bone scan** is highly sensitive for detecting **osteoblastic activity**, which is characteristic of most bone metastases. - It involves injecting a **radioactive tracer** (usually technetium-99m methylene diphosphonate) that accumulates in areas of increased bone turnover, making it excellent for surveying the entire skeletal system. *PET scan* - While a **PET scan** (Positron Emission Tomography) can detect bone metastases, especially with **FDG-PET**, it is generally more expensive and may not be as sensitive for purely **osteoblastic lesions** as a bone scan. - Its primary role is often in assessing metabolic activity of the primary tumor and other distant soft tissue metastases. *CT* - **CT scans** (Computed Tomography) are excellent for assessing bone anatomy, cortical destruction, and soft tissue involvement, but they are generally less sensitive for detecting early or widespread **osseous metastatic disease** compared to a bone scan. - CT provides detailed anatomical information but may miss early **marrow involvement** that alters bone metabolism. *Intravenous venogram* - An **intravenous venogram** is an imaging technique used to visualize veins, primarily for detecting **thrombosis** or venous insufficiency. - It has no role in the detection of **bone metastases**, as it provides no information about bone structure or metabolic activity.
Question 5: Which of the following tumours is radiosensitive?
- A. Ewing's sarcoma (Correct Answer)
- B. Osteosarcoma
- C. Hepatocellular carcinoma
- D. Malignant melanoma
Explanation: ***Ewing's sarcoma*** - **Ewing's sarcoma** is highly radiosensitive, meaning radiation therapy is an effective treatment modality, often used as a primary or adjuvant therapy. - Its high responsiveness to radiation helps control local disease and improve patient outcomes, especially when combined with chemotherapy. *Osteosarcoma* - **Osteosarcoma** is generally considered radioresistant, meaning it responds poorly to radiation therapy. - While radiation may be used in specific palliative settings, it is not a primary curative treatment for osteosarcoma, which primarily relies on surgery and chemotherapy. *Hepatocellular carcinoma* - **Hepatocellular carcinoma (HCC)** is largely radioresistant, and external beam radiation therapy has limited efficacy as a stand-alone treatment. - While certain advanced techniques like stereotactic body radiation therapy (SBRT) can be used for localized control, it is not considered broadly radiosensitive. *Malignant melanoma* - **Malignant melanoma** is historically considered highly radioresistant, requiring very high doses of radiation for any significant tumor control. - In recent years, high-dose, hypofractionated radiation therapy has shown some promise for local control, but it is not a universally radiosensitive tumor.
Question 6: Which of the following is a bone-forming malignant tumor?
- A. Osteoid osteoma
- B. Osteosarcoma (Correct Answer)
- C. Chondroblastoma
- D. Giant cell tumor
Explanation: ***Osteosarcoma*** - **Osteosarcoma** is the most common **primary malignant bone tumor**, characterized by the production of **osteoid** (immature bone) by malignant osteoblasts [1], [2]. - It typically arises in the **metaphysis of long bones** (e.g., distal femur, proximal tibia, proximal humerus) and often presents with pain and swelling [1], [2]. *Osteoid osteoma* - **Osteoid osteoma** is a benign bone tumor characterized by a small nidus of **osteoid-forming tissue** surrounded by sclerotic bone. - While it involves osteoid formation, it is **not malignant** and does not metastasize. *Chondroblastoma* - **Chondroblastoma** is a rare, **benign cartilage-forming tumor** that typically occurs in the **epiphysis of long bones** in skeletally immature individuals. - It is composed of chondroblast-like cells and does not produce osteoid or show malignant features. *Giant cell tumor* - **Giant cell tumor** of bone is an **aggressive, locally destructive benign tumor** characterized by numerous osteoclast-like giant cells and spindle-shaped stromal cells. - It arises in the **epiphysis/metaphysis** of long bones (e.g., distal femur, proximal tibia) but is not a bone-forming tumor and is typically not malignant, though it has a high recurrence rate. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 671-674. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1200-1202.
Question 7: Which of the following is an epiphyseal lesion?
- A. Fibrosarcoma
- B. Chondroblastoma (Correct Answer)
- C. Chondrosarcoma
- D. Non-ossifying fibroma
Explanation: **Chondroblastoma** - **Chondroblastoma** is a rare, benign bone tumor that typically arises in the **epiphysis** of long bones before epiphyseal fusion. - It specifically originates from **chondroblasts** within the epiphyseal growth plate region. *Fibrosarcoma* - **Fibrosarcoma** is a malignant tumor of fibrous connective tissue origin, typically found in the **metaphysis** or **diaphysis** of long bones. - It rarely affects the **epiphyseal** region and is characterized by aggressive local invasion and metastases. *Chondrosarcoma* - **Chondrosarcoma** is a malignant tumor of cartilage, commonly arising in the **metaphysis** or **diaphysis** of long bones, particularly the femur, humerus, and pelvis. - While it involves cartilage, its typical location is not primarily **epiphyseal** and it is characterized by malignant cartilaginous matrix. *Non-ossifying fibroma* - A **non-ossifying fibroma** (NOF), also known as a fibrous cortical defect, is a common benign fibrous lesion typically found in the **metaphysis** of long bones. - These lesions are usually asymptomatic and self-limiting, often resolving spontaneously, and do not originate in the **epiphysis**.
Question 8: Which of the following are features of Gorham's disease (Disappearing Bones)?
- A. Progressive disappearance of bone associated with multiple hemangiomatosis or multiple lymphangiectasis
- B. Usually the progression involves contiguous bones, but occasionally multiple sites are affected
- C. Patients present with mild pain or with pathological fracture
- D. All of the above (Correct Answer)
Explanation: **Gorham’s Disease**, also known as **Vanishing Bone Disease** or Phantom Bone Disease, is a rare musculoskeletal condition characterized by the spontaneous, progressive destruction and resorption of bone tissue. ### **Explanation of Options** * **Option A:** The hallmark of Gorham’s disease is the proliferation of thin-walled vascular or lymphatic channels within the bone. This leads to **progressive osteolysis** (bone disappearance) associated with **hemangiomatosis** or **lymphangiectasis**. The bone is replaced by fibrous connective tissue. * **Option B:** The disease typically spreads across joints to involve **contiguous bones** (e.g., spreading from the humerus to the scapula or from one vertebra to the next). While localized, it can occasionally manifest in multiple non-contiguous anatomical sites. * **Option C:** The clinical presentation is often insidious. Patients may experience **dull aching pain**, localized swelling, or a **pathological fracture** following minor trauma. In severe cases involving the ribs or spine, it can lead to chylothorax. Since all statements accurately describe the pathophysiology, progression, and clinical presentation of the disease, **Option D (All of the above)** is the correct answer. ### **High-Yield Clinical Pearls for NEET-PG** * **Radiology:** Characterized by "tapering" of the ends of remaining bone (sucker-stick appearance) and eventual complete disappearance of the bone shadow. * **Key Feature:** Unlike most bone tumors, Gorham’s disease **crosses joint spaces** to involve adjacent bones. * **Biopsy:** Shows non-malignant proliferation of thin-walled vessels; there is a notable **absence of osteoclasts** (the resorption is mediated by the vascular tissue). * **Complication:** **Chylothorax** is a life-threatening complication if the disease involves the thoracic cage.
Question 9: Onion peel appearance on radiograph is not seen in which of the following conditions?
- A. Garre's osteomyelitis
- B. Ewing's sarcoma
- C. Osteogenic sarcoma
- D. Fibrous dysplasia (Correct Answer)
Explanation: **Explanation:** The "onion peel" appearance (lamellated periosteal reaction) is a radiographic sign caused by the rhythmic or episodic lifting of the periosteum, leading to the deposition of multiple concentric layers of new bone. **1. Why Fibrous Dysplasia is the Correct Answer:** Fibrous dysplasia is a benign fibro-osseous lesion where normal bone is replaced by fibrous tissue and immature trabeculae. It is an **intramedullary** process that does not typically involve the periosteum. Therefore, it does not produce a periosteal reaction. Its classic radiographic appearance is described as **"Ground-glass opacification"** with a well-defined "rind" of sclerotic bone. **2. Analysis of Incorrect Options:** * **Ewing’s Sarcoma:** This is the classic association for onion peel appearance. The aggressive nature of this tumor causes rapid, successive layers of periosteal bone formation. * **Garre’s Osteomyelitis:** Also known as Chronic Sclerosing Osteomyelitis with proliferative periostitis. It is a low-grade chronic infection (often in the mandible) that stimulates the periosteum to form reactive peripheral bone in a lamellated pattern. * **Osteogenic Sarcoma (Osteosarcoma):** While "Sunburst" and "Codman’s triangle" are more common, Osteosarcoma is a highly aggressive tumor that can occasionally present with a lamellated (onion peel) appearance depending on the rate of tumor growth. **Clinical Pearls for NEET-PG:** * **Onion Peel Appearance:** Seen in Ewing’s sarcoma, Garre’s osteomyelitis, Osteosarcoma, and sometimes Langerhans Cell Histiocytosis (LCH). * **Ground Glass Appearance:** Pathognomonic for Fibrous Dysplasia. * **Sunburst/Sunray Appearance:** Highly suggestive of Osteosarcoma. * **Codman’s Triangle:** Indicates an aggressive process (malignancy or subperiosteal abscess) lifting the periosteum rapidly.
Question 10: Chemotherapy of Ewing's sarcoma includes all except?
- A. Doxorubicin
- B. Dactinomycin
- C. Topotecan
- D. 5-Fluorouracil (Correct Answer)
Explanation: **Explanation:** Ewing’s Sarcoma is a highly malignant, small round blue cell tumor that is exquisitely sensitive to chemotherapy. The standard of care involves a multimodal approach (Chemotherapy + Surgery/Radiotherapy). **Why 5-Fluorouracil (5-FU) is the correct answer:** 5-Fluorouracil is an antimetabolite primarily used in the treatment of epithelial malignancies (GI tract, breast, and head/neck cancers). It has **no established role** in the management of Ewing’s Sarcoma. **Analysis of other options (The VAC-IE Regimen):** The current standard chemotherapy for Ewing's Sarcoma follows the **VAC-IE** protocol, which includes: * **Vincristine** * **Actinomycin D (Dactinomycin):** An antitumor antibiotic that inhibits RNA synthesis (Option B). * **Cyclophosphamide** * **Ifosfamide** * **Etoposide** * **Doxorubicin (Adriamycin):** An anthracycline that is a cornerstone in treating both Ewing’s and Osteosarcoma (Option A). * **Topotecan:** A Topoisomerase I inhibitor often used in second-line or salvage therapy for recurrent/refractory Ewing’s Sarcoma (Option C). **High-Yield Clinical Pearls for NEET-PG:** * **Genetics:** Characterized by the **t(11;22)** translocation, leading to the **EWS-FLI1** fusion gene. * **Radiology:** Classic **"Onion-peel"** periosteal reaction. * **Histology:** Small round blue cells that are **PAS positive** (due to cytoplasmic glycogen) and express **CD99 (MIC-2).** * **Site:** Most common in the diaphysis of long bones (Femur is most common). * **Prognosis:** The most important prognostic factor is the presence of metastasis at the time of diagnosis (Lungs and Bone marrow are common sites).
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