Bone Tumors — MCQs

Bone Tumors Indian Medical PG Practice Questions and MCQs

Question 81: Jaffe's syndrome is defined as which of the following?

A. Fibrous dysplasia.
B. Fibrous dysplasia with cafe au lait spots. (Correct Answer)
C. Fibrous dysplasia with cafe au lait spots and endocrinal abnormalities.
D. None of the above.

Explanation: ### Explanation **Fibrous Dysplasia** is a benign bone condition where normal bone is replaced by fibrous connective tissue and haphazardly arranged bony trabeculae. It presents in three distinct clinical patterns, and distinguishing between them is high-yield for NEET-PG. **1. Why Option B is Correct:** **Jaffe’s Syndrome** (also known as Jaffe-Lichtenstein Syndrome) is a specific subtype of polyostotic fibrous dysplasia. It is defined by the clinical dyad of: * **Polyostotic Fibrous Dysplasia:** Involvement of multiple bones. * **Café-au-lait spots:** Hyperpigmented skin lesions, typically with irregular "Coast of Maine" borders. **2. Why the Other Options are Incorrect:** * **Option A:** Fibrous dysplasia alone can be **monostotic** (single bone, 70% of cases) or **polyostotic** (multiple bones). Jaffe’s syndrome specifically requires the presence of cutaneous pigmentation. * **Option C:** This describes **McCune-Albright Syndrome**. It is characterized by the triad of polyostotic fibrous dysplasia, café-au-lait spots, and **hyperfunctioning endocrinopathies** (most commonly precocious puberty in girls). While Jaffe’s and McCune-Albright are related, the presence of endocrine dysfunction is the differentiating factor. **3. High-Yield Clinical Pearls for NEET-PG:** * **Genetic Mutation:** Both Jaffe’s and McCune-Albright are caused by a post-zygotic mutation in the **GNAS1 gene**. * **Radiology:** Look for the characteristic **"Ground-glass appearance"** and "Shepherd’s crook deformity" of the femur. * **Histology:** Features "Chinese letter" patterns of trabeculae without osteoblastic rimming. * **Mazabraud Syndrome:** A rare association of fibrous dysplasia with soft tissue myxomas.

Question 82: A swelling over the distal end of the femur with secondary deposits in the lungs is diagnosed as:

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

Explanation: **Explanation:** **Osteogenic Sarcoma (Osteosarcoma)** is the most common primary malignant bone tumor in children and young adults. It typically arises in the **metaphysis** of long bones, with the **distal femur** being the most frequent site (around 40% of cases). A hallmark of Osteosarcoma is its high propensity for **early hematogenous spread**, specifically to the **lungs**. The presence of "skip lesions" and pulmonary metastases at the time of diagnosis is a classic clinical presentation for this malignancy. **Why other options are incorrect:** * **Giant Cell Tumor (GCT) / Osteoclastoma:** These terms refer to the same entity. GCT is a "locally aggressive" tumor but is typically benign. It occurs in the **epiphysis** (after physeal closure) and rarely metastasizes to the lungs (only in <2% of cases, known as "benign pulmonary implants"). * **Ewing’s Sarcoma:** While it is a highly malignant tumor that metastasizes to the lungs, it typically involves the **diaphysis** (shaft) of long bones and presents with systemic symptoms like fever and an "onion-peel" periosteal reaction. **NEET-PG High-Yield Pearls:** * **Radiology:** Look for the "Sunray appearance" or "Sunburst appearance" and "Codman’s triangle" (periosteal elevation). * **Enzyme Marker:** Serum **Alkaline Phosphatase (ALP)** is often elevated and serves as a marker for prognosis and treatment response. * **Age Group:** Bimodal distribution (10–20 years and >60 years associated with Paget’s disease). * **Treatment:** Neoadjuvant chemotherapy → Limb salvage surgery → Adjuvant chemotherapy.

Question 83: Which of the following is not a common cause of osteolytic lesions?

A. Prostate cancer (Correct Answer)
B. Breast cancer
C. Thyroid cancer
D. Bronchogenic carcinoma

Explanation: **Explanation:** The key to answering this question lies in distinguishing between **osteolytic** (bone-destroying) and **osteoblastic** (bone-forming) lesions. **1. Why Prostate Cancer is the Correct Answer:** Prostate cancer is the classic example of a malignancy that produces **osteoblastic (sclerotic) metastases**. This occurs because prostate cancer cells secrete factors like Bone Morphogenetic Proteins (BMPs) and TGF-β, which stimulate osteoblast activity, leading to increased bone density on X-rays. While it can occasionally have mixed features, it is the least likely among the options to present as a purely osteolytic lesion. **2. Analysis of Incorrect Options (Common Causes of Osteolytic Lesions):** * **Breast Cancer:** Typically presents as **mixed** lesions (both lytic and blastic), but osteolytic lesions are very common due to the secretion of PTHrP, which activates osteoclasts. * **Thyroid Cancer:** Characteristically produces **purely osteolytic**, highly vascular, and "expansile" (blow-out) lesions. * **Bronchogenic Carcinoma (Lung):** Primarily produces **osteolytic** lesions. Lung cancer is also the most common primary to metastasize to the bones of the hand and feet (acrometastasis). **3. NEET-PG High-Yield Pearls:** * **Mnemonic for Osteolytic Metastases:** "Lead Kettle" (**Li**ve, **K**idney, **E**sophagus, **T**hyroid, **T**estis, **L**ung, **E**nteric). * **Most common source of bone metastasis in males:** Prostate cancer. * **Most common source of bone metastasis in females:** Breast cancer. * **Purely Lytic Lesions:** Kidney (RCC) and Thyroid (often present with "pulsatile" bone secondary). * **Investigation of Choice:** **MRI** is the most sensitive for detecting early marrow involvement, while a **Bone Scan** (Technetium-99m) is used for screening (Note: Bone scans may be "cold" in purely lytic lesions like Multiple Myeloma).

Question 84: Secondaries are common in all the following locations EXCEPT:

A. Skull
B. Hand and feet bones (Correct Answer)
C. Proximal limb bones
D. Vertebrae

Explanation: **Explanation:** The distribution of skeletal metastases (secondaries) is primarily determined by the presence of **red bone marrow** and the **Batson’s venous plexus**. Metastatic cells preferentially seed in vascular, marrow-rich areas. **1. Why "Hand and feet bones" is the correct answer:** Bones distal to the elbow and knee (acral bones) contain very little red marrow in adults, as it is replaced by fatty yellow marrow. Consequently, metastases to the hands and feet are extremely rare. When they do occur (acrometastasis), the most common primary source is **Lung Cancer**. **2. Analysis of incorrect options:** * **Vertebrae (Option D):** This is the **most common site** for skeletal secondaries. The Batson’s plexus (a valveless venous system) allows direct retrograde spread of tumor cells from the pelvis, prostate, and breasts to the spine. * **Proximal limb bones (Option C):** The femur and humerus (proximal to the knee and elbow) retain significant red marrow throughout life, making them frequent sites for secondary deposits. * **Skull (Option A):** The skull contains diploic space with active marrow and is a common site for hematogenous spread, particularly from breast and lung primaries. **NEET-PG High-Yield Pearls:** * **Most common bone tumor overall:** Secondaries (Metastatic bone disease). * **Most common primary bone tumor:** Multiple Myeloma (if excluded, then Osteosarcoma). * **Commonest source of bone secondaries:** * Males: Prostate cancer (usually Osteoblastic). * Females: Breast cancer (usually Osteolytic/Mixed). * **Route of spread:** Most commonly hematogenous. * **Investigation of choice:** **PET-CT** or **Bone Scan** (Technetium-99m) are highly sensitive, except in Multiple Myeloma where X-rays/MRI are preferred.

Question 85: What diagnosis is suggested by the findings on this anteroposterior radiograph of the right tibia?

A. Ewing's sarcoma
B. Marrow hyperplasia (Correct Answer)
C. Osteomalacia
D. Polyostotic fibrous dysplasia

Explanation: ***Marrow hyperplasia*** - Characterized by **widened medullary cavity** and **thinned cortex** on radiographs, commonly seen in **hemolytic anemias** like sickle cell disease or thalassemia. - Shows **coarsened trabecular pattern** due to increased **erythropoietic activity** expanding the bone marrow space. *Ewing's sarcoma* - Presents with **aggressive permeative bone destruction** and characteristic **onion-skin periosteal reaction** on radiographs. - Typically shows a **soft tissue mass** with bone destruction, not marrow expansion patterns. *Osteomalacia* - Characterized by **Looser zones** (pseudofractures) and **generalized osteopenia** due to **vitamin D deficiency** or phosphate disorders. - Shows **delayed mineralization** and **bowing deformities**, not medullary cavity widening. *Polyostotic fibrous dysplasia* - Demonstrates **ground-glass appearance** with **well-defined sclerotic margins** and **shepherd's crook deformity** in proximal femur. - Shows **fibrous tissue replacement** of normal bone, creating characteristic **cystic lesions** with expansion.

Question 86: Osteoclastic giant cells are seen in all conditions except?

A. Osteoclastoma
B. Osteoblastoma
C. Aneurysmal bone cyst (Correct Answer)
D. Chondroblastoma

Explanation: **Explanation:** The presence of **multinucleated giant cells** is a common histological feature in several bone tumors, but their distribution and diagnostic significance vary. **Why Option C is the correct answer:** While **Aneurysmal Bone Cyst (ABC)** does contain giant cells within its fibrous septa, the question asks for conditions where osteoclastic giant cells are a defining or prominent feature. In the context of standard PG entrance exams, ABC is often the "except" choice because its primary pathology is the presence of blood-filled, sinusoidal spaces separated by fibrous stroma. However, it is important to note that this question is controversial as ABC *does* contain giant cells. In many classic MCQ banks, this question is used to highlight that giant cells are "incidental" in ABC compared to the other options where they are more characteristic. **Analysis of other options:** * **A. Osteoclastoma (Giant Cell Tumor):** As the name suggests, this is the classic "Giant Cell Tumor." It is characterized by a "monotonous" field of mononuclear stromal cells interspersed with numerous large, multinucleated osteoclastic giant cells. * **B. Osteoblastoma:** This is a bone-forming tumor. While it primarily consists of osteoblasts and osteoid, it frequently contains scattered osteoclast-like giant cells, especially in areas of bone remodeling. * **D. Chondroblastoma:** This is a cartilaginous tumor occurring in the epiphysis. Histologically, it shows "chicken-wire calcification" and is well-known for containing numerous osteoclast-like giant cells. **NEET-PG High-Yield Pearls:** * **Epiphyseal tumors:** Chondroblastoma and Giant Cell Tumor (GCT). * **GCT (Osteoclastoma):** "Soap bubble" appearance on X-ray; occurs in the 20-40 age group. * **Chondroblastoma:** Characterized by "Chicken-wire" calcification. * **ABC:** Characterized by "Fluid-fluid levels" on MRI and a "Blow-out" appearance on X-ray. * **Other Giant Cell containing lesions:** Brown tumor of hyperparathyroidism, Non-ossifying fibroma (NOF), and Unicameral bone cyst.

Question 87: Which of the following is NOT true about osteoid osteoma?

A. It is a benign bone tumor.
B. Pain is not relieved by salicylates. (Correct Answer)
C. Bone scan shows increased uptake in the lesion.
D. X-ray shows a dense lesion.

Explanation: **Explanation:** Osteoid osteoma is a common benign, bone-forming tumor characterized by a small radiolucent core called a **nidus** (less than 2 cm) surrounded by a zone of reactive bone formation (sclerosis). **1. Why Option B is the correct answer (The False Statement):** The hallmark clinical feature of osteoid osteoma is **nocturnal pain** that is **exquisitely relieved by salicylates (Aspirin) or NSAIDs**. This occurs because the nidus contains high concentrations of prostaglandins (PGE2 and PGI2). Since the question asks for the statement that is *NOT* true, Option B is the correct choice because pain *is* relieved by these medications. **2. Analysis of Incorrect Options:** * **Option A:** It is indeed a **benign** tumor, typically affecting children and young adults (10–25 years). * **Option C:** Bone scans are highly sensitive for osteoid osteoma. They show a **"double density sign"** (intense uptake in the nidus surrounded by a less intense area of uptake in the reactive bone), making it useful for localization. * **Option D:** On X-ray, the lesion appears as a **dense, sclerotic area** of bone. The central radiolucent nidus may sometimes be obscured by this intense surrounding sclerosis, requiring a CT scan for better visualization. **NEET-PG High-Yield Pearls:** * **Most common site:** Femur (specifically the neck) and Tibia. * **Gold Standard Investigation:** Thin-cut **CT Scan** (best to visualize the nidus). * **Histology:** Shows a nidus of haphazardly arranged osteoid trabeculae with prominent osteoblasts. * **Management:** Medical management with NSAIDs is the first line. If refractory, **Radiofrequency Ablation (RFA)** is the treatment of choice. * **Differential Diagnosis:** Osteoblastoma (nidus >2 cm, pain not relieved by aspirin).

Question 88: A 25-year-old man presents with severe pain in the left femur. The pain is relieved by aspirin. On plain film, a 0.5-cm lucent lesion, which is surrounded by marked reactive sclerosis, is seen. What type of bone lesion is most likely associated with these findings?

A. Osteoma
B. Osteoid osteoma (Correct Answer)
C. Osteoblastoma
D. Osteosarcoma

Explanation: **Explanation:** The clinical presentation is classic for **Osteoid Osteoma**, a benign bone-forming tumor. The diagnosis is based on three hallmark features: 1. **Clinical:** Severe nocturnal pain that is characteristically relieved by **NSAIDs/Aspirin**. This occurs because the tumor produces high levels of prostaglandins. 2. **Radiological:** A small radiolucent zone called a **nidus** (typically <1.5–2 cm). 3. **Reactive Changes:** The nidus is surrounded by a significant zone of **perifocal reactive sclerosis** (dense bone formation). **Analysis of Incorrect Options:** * **A. Osteoma:** These are slow-growing, dense ivory-like bony masses, most commonly found in the skull and paranasal sinuses. They are asymptomatic and do not present with a radiolucent nidus. * **C. Osteoblastoma:** Often called "giant osteoid osteoma," it has a nidus >2 cm. Crucially, the pain is **not** relieved by aspirin, and there is much less reactive sclerosis compared to osteoid osteoma. It most commonly affects the posterior elements of the spine. * **D. Osteosarcoma:** A highly malignant tumor typically seen in the metaphyseal region of long bones. It presents with systemic symptoms, a large soft tissue mass, and aggressive radiological features like Sunburst appearance or Codman’s triangle, rather than a small, sclerotic-rimmed nidus. **High-Yield Pearls for NEET-PG:** * **Most common site:** Proximal Femur (neck). * **Gold Standard Investigation:** Contrast-enhanced CT scan (best to visualize the nidus). * **Pathology:** The nidus consists of interlacing osteoid trabeculae. * **Management:** Medical management with NSAIDs; if refractory, **Radiofrequency Ablation (RFA)** is the treatment of choice.

Question 89: Which of the following is a specific marker for Ewing's sarcoma?

A. CD 45
B. CD 99 (Correct Answer)
C. HMB-45
D. CD1a

Explanation: **Explanation:** **CD 99 (MIC2 gene product)** is the most sensitive marker for **Ewing’s Sarcoma** and Primitive Neuroectodermal Tumors (PNET). It is a cell surface glycoprotein that shows a characteristic strong, diffuse membranous staining pattern on immunohistochemistry (IHC). While highly sensitive, it is not 100% specific, as it can occasionally be seen in lymphoblastic lymphoma or synovial sarcoma; however, in the context of a "small round blue cell tumor" of the bone, it is the diagnostic gold standard for Ewing’s. **Analysis of Incorrect Options:** * **CD 45 (Leukocyte Common Antigen):** This is a marker for hematopoietic cells. It is used to identify **Lymphoma**, which is a key differential diagnosis for small round blue cell tumors in bone. * **HMB-45 (Human Melanoma Black):** This is a specific marker for **Melanoma** and clear cell sarcoma. It is not expressed in Ewing’s sarcoma. * **CD1a:** This is a specific marker for **Langerhans Cell Histiocytosis (LCH)**, along with S100 and Langerin (CD207). **NEET-PG High-Yield Pearls:** * **Genetics:** Ewing’s sarcoma is characterized by the **t(11;22)(q24;q12)** translocation, resulting in the **EWS-FLI1** fusion gene. * **Radiology:** Classic "Onion-skin" periosteal reaction. * **Site:** Most commonly affects the **diaphysis** of long bones (Femur > Tibia > Humerus). * **Histology:** Small round blue cells with scanty cytoplasm and **Homer-Wright rosettes** (indicating neural differentiation).

Question 90: Bone metastases is common in which of the following?

A. Nephroblastoma
B. Neuroblastoma
C. Renal Cell Carcinoma (RCC) (Correct Answer)
D. Clear cell sarcoma

Explanation: **Explanation:** **Bone Metastases in Renal Cell Carcinoma (RCC)** Renal Cell Carcinoma (RCC) is one of the most common primary malignancies that metastasize to the bone. The underlying medical concept is that RCC typically produces **purely osteolytic lesions**. These metastases are characteristically highly vascular (pulsatile) and often present with pathological fractures. In adults, the most common primaries spreading to bone follow the mnemonic **PB-KTL** (Prostate, Breast, Kidney, Thyroid, Lung). **Analysis of Options:** * **Renal Cell Carcinoma (RCC):** Correct. It is a classic cause of lytic bone metastasis in adults. * **Nephroblastoma (Wilms Tumor):** Incorrect. While it is the most common renal tumor in children, it rarely metastasizes to the bone; it primarily spreads to the lungs. * **Neuroblastoma:** Incorrect. Although Neuroblastoma *does* frequently metastasize to the bone (especially the skull and orbit), in the context of standard orthopedic and surgical teaching for exams like NEET-PG, RCC is the classic "high-yield" answer for renal-origin bone metastasis. * **Clear Cell Sarcoma of the Kidney (CCSK):** This is known as the "Bone Seeking Tumor of the Kidney" in children. However, it is a rare variant compared to the high prevalence of RCC in the general population. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site of bone metastasis:** Spine (followed by femur and pelvis). * **Osteoblastic (Sclerotic) Metastasis:** Most common in Prostate cancer. * **Osteolytic Metastasis:** Most common in RCC, Lung, and Thyroid cancer. * **Mixed Lesions:** Most common in Breast cancer. * **Pulsatile Bone Secondary:** Think RCC or Follicular Carcinoma of the Thyroid. * **Investigation of choice:** Bone Scan (Technetium-99m) is highly sensitive, but for RCC (which is purely lytic), a bone scan may occasionally be "cold"; hence, X-rays or MRI are vital.

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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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