Bone Tumors — MCQs

Bone Tumors Indian Medical PG Practice Questions and MCQs

Question 111: A 30-year-old male presented with hip pain for the last 6 months. A hip X-ray is provided. What is the likely diagnosis?

A. Giant cell tumor (Correct Answer)
B. Simple bone cyst
C. Adamantinoma
D. Ewing's sarcoma

Explanation: ***Giant cell tumor*** - Typically occurs in the **epiphyseal region** of long bones in patients aged **20-40 years**, matching this 30-year-old male presentation. - Characteristically presents as an **eccentric lytic lesion** with a **soap-bubble appearance** on X-ray, commonly affecting the **proximal femur** near the hip. *Simple bone cyst* - Usually affects **younger patients** (children and adolescents) and occurs in the **metaphyseal region**, not the epiphysis. - Presents as a **central, well-defined lytic lesion** without the eccentric location typical of giant cell tumors. *Adamantinoma* - Predominantly affects the **tibia** (85-90% of cases) rather than the hip region. - Shows **biphasic histology** with epithelial and osteofibrous components, and typically occurs in the **diaphysis**. *Ewing's sarcoma* - More commonly affects **younger patients** (10-20 years) and typically involves the **diaphyseal region**. - Characteristically shows **onion-skin periosteal reaction** on X-ray, which is not typical for hip lesions in 30-year-olds.

Question 112: Which of the following is a pulsatile tumor?

A. Osteosarcoma (Correct Answer)
B. Chondrosarcoma
C. Ewing's sarcoma
D. Osteoclastoma

Explanation: **Explanation:** The correct answer is **A. Osteosarcoma**. **Why Osteosarcoma is the correct answer:** Pulsatility in a bone tumor is a clinical sign of extreme vascularity. Osteosarcoma, particularly the **Telangiectatic variant**, is highly vascular and contains large, blood-filled sinusoidal spaces. When these tumors are rapidly growing and erode the cortex, the arterial pulsations are transmitted through the vascular mass, making it "pulsatile" on palpation. This is often associated with a loud **bruit** heard on auscultation. **Analysis of Incorrect Options:** * **B. Chondrosarcoma:** This is a cartilage-forming tumor. It is typically slow-growing and characterized by a firm, lobulated, and relatively avascular matrix. It does not exhibit pulsatility. * **C. Ewing’s Sarcoma:** While this tumor is highly aggressive and can mimic osteomyelitis (with fever and raised ESR), it is not inherently vascular enough to produce pulsations. * **D. Osteoclastoma (Giant Cell Tumor):** Although GCT is a locally aggressive and vascular tumor that can cause significant bone expansion ("Egg-shell crackling"), it is rarely pulsatile compared to Telangiectatic Osteosarcoma or Metastatic deposits. **NEET-PG High-Yield Pearls:** * **Differential Diagnosis of Pulsatile Bone Tumors:** 1. **Telangiectatic Osteosarcoma** (Primary) 2. **Metastatic Renal Cell Carcinoma (RCC)** (Most common secondary) 3. **Metastatic Thyroid Carcinoma** (Follicular variant) 4. **Aneurysmal Bone Cyst (ABC)** * **Radiology Tip:** Telangiectatic Osteosarcoma can mimic an Aneurysmal Bone Cyst on MRI (both show fluid-fluid levels), but the presence of solid nodular components and high-grade pleomorphism on biopsy confirms the malignancy.

Question 113: What is the most common primary site of a metastatic bone tumor in males?

A. Lung (Correct Answer)
B. Liver
C. Bone
D. Brain

Explanation: **Explanation:** The skeleton is the third most common site for metastatic disease, following the lung and liver. In males, the **lung** is the most common primary site that metastasizes to bone. While prostate cancer is a very frequent cause of bony metastases in elderly men (typically presenting as osteoblastic lesions), epidemiological data and NEET-PG standard references prioritize lung cancer due to its high incidence and aggressive metastatic potential. **Analysis of Options:** * **A. Lung (Correct):** Lung carcinoma is the leading primary source of bone metastasis in males. These lesions are typically **osteolytic** in nature. * **B. Liver:** The liver is a common site for metastasis *from* other organs (like the colon), but primary liver cancer (HCC) metastasizes to bone much less frequently than lung or prostate cancer. * **C. Bone:** This refers to primary bone tumors (e.g., Osteosarcoma). Metastatic bone disease, by definition, implies a primary tumor originating in a non-osseous organ. * **D. Brain:** Primary brain tumors (like Gliomas) rarely metastasize outside the central nervous system because of the blood-brain barrier and lack of lymphatic drainage. **High-Yield Clinical Pearls for NEET-PG:** * **Most common primary site (Overall):** Breast (Females), Lung (Males). * **Most common site of bone metastasis:** Spine (specifically the thoracic spine), followed by the pelvis and femur. * **Type of Lesion:** Most metastases are **osteolytic** (e.g., Lung, Kidney, Thyroid). **Prostate cancer** is the classic cause of **osteoblastic** (sclerotic) lesions. * **Route of spread:** Most commonly via the **Batson venous plexus** (a valveless vertebral venous system), which explains the high frequency of spinal involvement. * **Investigation of choice:** **Bone Scan (Technetium-99m)** is the most sensitive screening tool, except for Multiple Myeloma where it may be negative.

Question 114: Which of the following is not a type I geographic lesion of bone?

A. Fibrous dysplasia
B. Brodie's abscess
C. Giant cell tumor
D. Ewing's sarcoma (Correct Answer)

Explanation: The classification of bone destruction patterns (Lodwick classification) is a high-yield concept for NEET-PG. Bone lesions are categorized based on their margins, which indicate the rate of growth and the bone's biological response. **Explanation of the Correct Answer:** **D. Ewing’s Sarcoma** is the correct answer because it typically presents as a **Type III (Permeative)** or **Type II (Moth-eaten)** lesion. These patterns signify a highly aggressive, rapidly growing malignancy where the tumor infiltrates the bone so quickly that the host bone does not have time to form a distinct reactive margin. Radiologically, it lacks a clear border and often shows a "sunburst" or "onion-skin" periosteal reaction. **Explanation of Incorrect Options:** **Type I (Geographic)** lesions are slow-growing, well-defined radiolucencies. * **A. Fibrous Dysplasia:** Typically a Type IA or IB lesion. It is a benign fibro-osseous lesion with a well-defined "ground-glass" appearance. * **B. Brodie’s Abscess:** A subacute osteomyelitis that presents as a Type IA lesion—a well-defined radiolucency with a thick, sclerotic rim (reactive bone). * **C. Giant Cell Tumor (GCT):** Usually a Type IC lesion. While it is locally aggressive and lacks a sclerotic rim, it still maintains a distinct "geographic" transition zone at the epiphysis. **NEET-PG High-Yield Pearls:** * **Type IA:** Geographic with a sclerotic rim (e.g., Non-ossifying fibroma, Brodie’s abscess). * **Type IB:** Geographic without a sclerotic rim (e.g., Unicameral bone cyst). * **Type IC:** Geographic with ill-defined margins (e.g., GCT, Osteoblastoma). * **Permeative Pattern (Type III):** Classic for Ewing’s sarcoma and Lymphoma; indicates high-grade malignancy.

Question 115: Which of the following conditions shows a sun ray appearance on imaging?

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

Explanation: ### Explanation The **"Sunray" (or sunburst) appearance** is a classic radiological sign of an aggressive periosteal reaction. It occurs when the tumor grows so rapidly that the periosteum cannot form a solid layer of new bone; instead, the Sharpey’s fibers are stretched perpendicular to the bone, and ossification occurs along these fibers. **1. Why Ewing Sarcoma is Correct:** While the "Onion-peel" appearance (concentric layers of new bone) is the most classic description for Ewing Sarcoma, it frequently presents with a **Sunray appearance** or **Codman’s triangle** due to its highly aggressive nature and rapid cortical penetration. In recent NEET-PG patterns, Ewing Sarcoma is often associated with this finding alongside its typical diaphyseal location and "small round blue cell" histology. **2. Analysis of Incorrect Options:** * **A. Osteosarcoma:** This is the most common primary bone tumor to show a sunray appearance. However, in the context of this specific question (where Ewing is marked correct), it serves as a primary differential. Both show aggressive periosteal reactions. * **C. Osteoclastoma (Giant Cell Tumor):** Characteristically shows a **"Soap bubble" appearance**. It is an eccentric, epiphyseal lesion occurring after physeal closure. * **D. Multiple Myeloma:** Characteristically shows **"Punched-out" lytic lesions** (especially in the skull) and generalized osteopenia. It does not typically produce a periosteal reaction because the tumor cells inhibit osteoblastic activity. **High-Yield Clinical Pearls for NEET-PG:** * **Ewing Sarcoma:** Translocation **t(11;22)**, PAS positive, CD99 (MIC2) positive. * **Osteosarcoma:** Associated with RB1 and TP53 mutations; occurs at the metaphysis. * **Periosteal Reactions Summary:** * *Onion-peel:* Ewing Sarcoma. * *Sunburst/Sunray:* Osteosarcoma, Ewing Sarcoma. * *Codman’s Triangle:* Any aggressive lesion (Malignancy, Osteomyelitis).

Question 116: What is true about Ameloblastoma?

A. Cystic lesion (Correct Answer)
B. Rapidly growing
C. Malignant disease
D. Most common site is Tibia

Explanation: **Ameloblastoma** is a benign but locally aggressive odontogenic tumor arising from the dental epithelium. It is a high-yield topic in both Orthopaedics and Oral Surgery for NEET-PG. ### **Explanation of Options:** * **A. Cystic lesion (Correct):** Ameloblastoma characteristically presents as a **multilocular cystic lesion**. On X-ray, it classically shows a **"Soap-bubble" appearance** (large loculations) or a "Honey-comb" appearance (small loculations). These cysts are formed due to the breakdown of the central stellate reticulum-like cells within the tumor nests. * **B. Rapidly growing:** This is incorrect. Ameloblastoma is typically a **slow-growing**, painless expansion of the jaw. Rapid growth would suggest a secondary infection or malignant transformation. * **C. Malignant disease:** This is incorrect. It is a **benign** tumor. While it is "locally invasive" and has a high recurrence rate if not widely excised, true malignancy (metastatic ameloblastoma) is extremely rare. * **D. Most common site is Tibia:** This is incorrect. The **Mandible (molar-ramus region)** is the most common site (80%). The confusion often arises with *Adamantinoma*, a histologically similar tumor that occurs in the **Tibia**. ### **NEET-PG High-Yield Pearls:** * **Classic Radiographic Sign:** Soap-bubble appearance. * **Histology:** Palisading columnar cells at the periphery with a central area of loose stellate reticulum (Vickers-Gorlin criteria). * **Treatment:** Wide local excision (en bloc resection) is preferred over curettage due to the high risk of local recurrence. * **Differential Diagnosis:** Keratocystic Odontogenic Tumor (OKC) and Giant Cell Tumor (GCT).

Question 117: Which of the following tumors is associated with raised serum alkaline phosphatase levels?

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

Explanation: **Explanation:** **Osteosarcoma** is the correct answer because it is a primary malignant bone tumor characterized by the direct production of **osteoid (immature bone)** by tumor cells. Serum Alkaline Phosphatase (ALP) is an enzyme produced by **osteoblasts** during bone formation. In Osteosarcoma, the intense osteoblastic activity and rapid bone turnover lead to significantly elevated serum ALP levels. Clinically, ALP levels serve as a useful biochemical marker for monitoring disease activity, treatment response, and detecting recurrence or metastasis. **Analysis of Incorrect Options:** * **Osteoclastoma (Giant Cell Tumor):** This is a tumor of osteoclastic (bone-resorbing) origin. Since it is primarily a destructive lesion without significant new bone formation, ALP levels typically remain normal. * **Multiple Myeloma:** This is a plasma cell dyscrasia characterized by purely **lytic** bone lesions. A hallmark of Multiple Myeloma is the absence of osteoblastic activity; therefore, ALP levels are characteristically **normal**, which helps differentiate it from metastatic bone disease. * **Chondrosarcoma:** This is a malignant tumor of cartilage-forming cells. Since the matrix produced is cartilaginous rather than osteoid, it does not typically cause an elevation in serum ALP. **NEET-PG High-Yield Pearls:** * **ALP in Bone:** Elevated in Osteosarcoma, Paget’s disease, Healing fractures, and Rickets/Osteomalacia. * **Osteosarcoma Marker:** Besides ALP, **Lactate Dehydrogenase (LDH)** is also elevated and serves as a prognostic indicator (higher levels correlate with a poorer prognosis). * **Radiology:** Look for "Sunray appearance" and "Codman’s triangle" on X-ray for Osteosarcoma. * **Multiple Myeloma Tip:** If a question mentions "punched-out lytic lesions" with "normal ALP," think Multiple Myeloma.

Question 118: Mazabraud's syndrome is defined as:

A. Fibrous dysplasia with cafe au lait spots.
B. Fibrous dysplasia with intramuscular myxomas. (Correct Answer)
C. Fibrous dysplasia with peripheral neuritis.
D. None of the above.

Explanation: ### Explanation **Mazabraud’s syndrome** is a rare benign condition characterized by the association of **Fibrous Dysplasia (FD)** and **intramuscular myxomas**. 1. **Why Option B is correct:** The syndrome typically presents with polyostotic fibrous dysplasia (multiple bone involvement) and multiple soft tissue myxomas, usually located in the same anatomical region as the affected bones. Both conditions share a common molecular basis: a post-zygotic mutation in the **GNAS1 gene**, which leads to overproduction of intracellular cAMP, causing abnormal proliferation of stromal cells. 2. **Why other options are incorrect:** * **Option A:** Fibrous dysplasia associated with *café-au-lait* spots and precocious puberty (endocrinopathies) defines **McCune-Albright Syndrome**. While Mazabraud’s and McCune-Albright share the GNAS mutation, they are clinically distinct entities. * **Option C:** Fibrous dysplasia is not typically associated with peripheral neuritis. This option is a distractor. ### NEET-PG Clinical Pearls: * **Demographics:** More common in females; myxomas usually appear years after the bone lesions are identified. * **Radiology of FD:** Classically described as having a **"Ground Glass Appearance"** on X-ray due to the replacement of normal bone with fibrous tissue and immature trabeculae. * **Histology of FD:** Characterized by **"Chinese letter patterns"** (irregularly shaped trabeculae of woven bone without osteoblastic rimming). * **Malignant Transformation:** While rare, patients with Mazabraud’s syndrome have a slightly higher risk of the fibrous dysplasia transforming into **osteosarcoma** compared to those with isolated FD.

Question 119: What is the standard surgical staging system for bone tumors?

A. Edmonton
B. Manchester
C. Enneking (Correct Answer)
D. TNM

Explanation: The **Enneking Staging System** (also known as the MSTS system) is the gold standard for staging musculoskeletal tumors (bone and soft tissue sarcomas). Unlike the TNM system used for visceral cancers, the Enneking system is based on three specific factors: **Grade (G), Site (T), and Metastasis (M).** ### Why Enneking is Correct: The system categorizes tumors into: * **Grade (G):** G0 (Benign), G1 (Low grade), G2 (High grade). * **Site (T):** T1 (Intracompartmental), T2 (Extracompartmental). * **Metastasis (M):** M0 (No metastasis), M1 (Regional or distant metastasis). For malignant tumors, the stages are **I (Low grade), II (High grade), and III (Metastatic)**, further subdivided into **A (Intracompartmental)** and **B (Extracompartmental)**. This system is crucial because it guides the surgical margin required (e.g., radical vs. wide excision). ### Why Other Options are Incorrect: * **Edmonton:** Used for classifying symptoms in palliative care (Edmonton Symptom Assessment System). * **Manchester:** A staging system historically used for Breast Cancer. * **TNM:** While the AJCC uses a TNM system for bone cancers, the **Enneking system** remains the "standard" surgical staging taught in orthopaedics as it dictates the surgical approach based on anatomical compartments. ### High-Yield Clinical Pearls for NEET-PG: 1. **Benign Tumors (Enneking):** Staged as **1 (Latent)**, **2 (Active)**, and **3 (Aggressive)**. 2. **Compartments:** An anatomical compartment is a space bounded by natural barriers to tumor extension (e.g., cortical bone, joint capsule, or fascia). 3. **Skip Lesions:** These are smaller foci of tumor within the same bone but separate from the primary lesion; their presence automatically upgrades the tumor to **Stage III** (Enneking).

Question 120: A specimen shows a stalk-like resection of a pedunculated bony swelling. What is the most likely diagnosis?

A. Osteochondroma (Correct Answer)
B. Chondroma
C. Osteoid osteoma
D. Osteoclastoma

Explanation: ### Explanation **1. Why Osteochondroma is Correct:** Osteochondroma (Exostosis) is the most common benign bone tumor. It is characterized by a bony outgrowth covered by a cartilage cap. Morphologically, it presents in two forms: **pedunculated** (attached by a stalk) or **sessile** (broad-based). The presence of a "stalk-like" resection is pathognomonic for the pedunculated variety. A key diagnostic feature is that the cortex and the medullary cavity of the tumor are continuous with those of the host bone. **2. Why the Other Options are Incorrect:** * **Chondroma:** These are benign tumors of hyaline cartilage. **Enchondromas** occur within the medullary cavity (especially in short tubular bones of hands/feet), while **juxtacortical chondromas** occur on the surface but do not typically form a pedunculated bony stalk. * **Osteoid Osteoma:** This is a small, painful lesion characterized by a **nidus** (less than 2 cm) surrounded by a zone of reactive bone sclerosis. It does not present as a large pedunculated outgrowth. * **Osteoclastoma (Giant Cell Tumor):** This is an aggressive, **epiphyseal** lesion. Radiologically, it shows a "soap bubble" appearance and is characterized by bone destruction rather than a stalk-like bony protrusion. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Metaphysis of long bones (especially around the knee). * **Direction of growth:** It always grows **away from the joint** (towards the diaphysis). * **Genetics:** Associated with mutations in **EXT1 and EXT2** genes. * **Malignant Transformation:** Suggested if the cartilage cap thickness exceeds **2 cm** in adults (transforms into Chondrosarcoma). * **Multiple Hereditary Exostoses (Diaphyseal Aclasis):** An autosomal dominant condition featuring multiple osteochondromas.

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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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