Bone Tumors Practice Questions

Q: Which of the following statements about fibrous dysplasia is FALSE?

Biopsy is contraindicated.. ### Explanation **Fibrous Dysplasia** is a benign, non-neoplastic condition where normal bone is replaced by fibrous tissue and immature, woven bone. **Why Option D is the Correct (False) Statement:** Biopsy is **not contraindicated** in fibrous dysplasia. While the diagnosis is often made radiologically (showing a characteristic "ground-glass" appearance), a biopsy is frequently performed to confirm the diagnosis or to rule out malignancy (like low-grade osteosarcoma) if the presentation is atypical. Histology classically shows "Chinese letter" patterns of trabeculae without osteoblastic rimming. **Analysis of Other Options:** * **Option A (True):** McCune-Albright syndrome is a triad of polyostotic fibrous dysplasia, café-au-lait spots (Coast of Maine borders), and precocious puberty (hyperendocrinopathy). * **Option B (True):** Mazabraud syndrome is the rare association of fibrous dysplasia (usually polyostotic) with multiple soft tissue myxomas. * **Option C (True):** The "Shepherd's Crook" deformity is a classic complication where the proximal femur undergoes progressive varus deformity due to repeated microfractures in the weakened dysplastic bone. --- ### NEET-PG High-Yield Pearls * **Genetics:** Caused by a somatic mutation in the **GNAS1 gene**. * **Radiology:** Characterized by a **"Ground-glass" appearance** and expansion of the bone with thinning of the cortex. * **Monostotic vs. Polyostotic:** Monostotic (single bone) is the most common form (70-80%). * **Management:** Asymptomatic lesions are observed. Bisphosphonates may help with bone pain. Surgery (curettage and bone grafting) is indicated for impending fractures or significant deformity, though recurrence is common.

Q: Which of the following is an epiphyseal origin tumor?

Osteoclastoma. **Explanation:** The location of a bone tumor within the long bone (epiphysis, metaphysis, or diaphysis) is a high-yield diagnostic marker in orthopaedics. **1. Why Osteoclastoma is correct:** **Osteoclastoma (Giant Cell Tumor - GCT)** is a classic **epiphyseal** tumor. It typically occurs after the growth plate has closed (ages 20–40). It is characterized by an eccentric location and a "soap-bubble" appearance on X-ray. It originates in the epiphysis but frequently extends into the metaphysis. **2. Why the other options are incorrect:** * **Osteogenic Sarcoma (Osteosarcoma):** This is primarily a **metaphyseal** tumor. It occurs in the most metabolically active growth regions, such as the distal femur or proximal tibia, typically in adolescents. * **Ewing’s Sarcoma:** This is a **diaphyseal** (shaft) tumor. It is a small round blue cell tumor that often presents with an "onion-peel" periosteal reaction. * **Osteoblastoma:** This tumor most commonly involves the **posterior elements of the spine** (lamina and pedicles). When it occurs in long bones, it is usually metaphyseal or diaphyseal, not epiphyseal. **Clinical Pearls for NEET-PG:** * **Epiphyseal Tumors:** Remember the mnemonic **"GEC"** — **G**iant Cell Tumor (Osteoclastoma), **E**nchondroma (in small bones), and **C**hondroblastoma (the only true epiphyseal tumor in children with open physis). * **Metaphyseal Tumors:** Most common site for tumors (Osteosarcoma, Osteochondroma, Simple Bone Cyst). * **Diaphyseal Tumors:** Ewing’s Sarcoma, Adamantinoma, Osteoid Osteoma, and Eosinophilic Granuloma. * **GCT Key Fact:** It is "locally malignant" and the most common site is the **distal femur.**

Q: An 8-year-old boy presented with pain in the arm. X-ray demonstrates an expansile lesion in the metaphysis of the upper humerus with breach of the overlying cortex. What is the most likely diagnosis?

Aneurysmal bone cyst. ### **Explanation** The correct answer is **Aneurysmal Bone Cyst (ABC)**. **1. Why Aneurysmal Bone Cyst is correct:** ABC is a benign but locally aggressive, blood-filled reactive bone lesion. It typically occurs in the first two decades of life (most common in patients <20 years). Radiologically, it presents as an **eccentric, expansile, "soap-bubble" lesion** in the metaphysis of long bones. A key distinguishing feature of ABC is its ability to **expand and breach/balloon the cortex** (though the periosteum remains intact), often appearing more aggressive than a simple cyst. **2. Why the other options are incorrect:** * **Unicameral Bone Cyst (UBC):** Also known as a Simple Bone Cyst, it is centrally located (not eccentric) and typically does not breach the cortex unless there is a pathological fracture (the "fallen leaf sign"). * **Chondroblastoma:** This is an **epiphyseal** tumor in children. The question specifies a metaphyseal lesion, making this unlikely. * **Osteoclastoma (Giant Cell Tumor):** While it is an expansile, eccentric lesion, it occurs in the **epiphysis** (after growth plate closure) and typically affects the age group of **20–40 years**. It is very rare in an 8-year-old. **3. NEET-PG High-Yield Pearls:** * **Location:** ABC is Metaphyseal; GCT is Epiphyseal; Osteosarcoma/Ewing’s is Diaphyseal/Metaphyseal. * **MRI Finding:** The pathognomonic sign for ABC on MRI is **Fluid-Fluid levels** (representing sedimented red blood cells). * **Genetics:** ABC is associated with the **USP6** gene rearrangement. * **Treatment:** Curettage and bone grafting; however, ABC has a higher recurrence rate compared to UBC.

Q: A 22-year-old male presents with a bony mass in the metaphyseal region of the right knee with a typical sun ray appearance. A CT scan of the chest reveals osteoblastic metastases. What is the most probable diagnosis?

Osteosarcoma. ### Explanation **Correct Answer: A. Osteosarcoma** The clinical presentation is classic for **Osteosarcoma**, the most common primary malignant bone tumor in young adults. * **Age & Location:** It typically occurs in the second decade of life (10–25 years) and favors the **metaphysis** of long bones, particularly around the knee (distal femur or proximal tibia). * **Radiological Hallmark:** The **"Sunray appearance"** (or sunburst) is caused by a rapid periosteal reaction where the tumor bone forms perpendicular to the cortex. * **Metastasis:** Osteosarcoma is highly hematogenous. The **lungs** are the most common site of metastasis, and the presence of **osteoblastic (bone-forming) nodules** in the chest CT is pathognomonic for metastatic osteosarcoma. --- ### Why Other Options are Incorrect: * **B. Chondrosarcoma:** Usually occurs in an older age group (40–60 years). Radiologically, it shows "popcorn calcification" rather than a sunray appearance. * **C. Ewing's Sarcoma:** Typically affects the **diaphysis** (shaft) of long bones. The characteristic periosteal reaction is **"onion-peeling"** (lamellated), and it is a small round blue cell tumor, not bone-forming. * **D. Osteochondroma:** A benign bone tumor (exostosis). It presents as a pedunculated or sessile growth away from the joint, with a characteristic cartilage cap and continuity with the marrow cavity. --- ### NEET-PG High-Yield Pearls: * **Codman’s Triangle:** Another periosteal reaction seen in Osteosarcoma (elevation of periosteum). * **Serum Marker:** Elevated **Alkaline Phosphatase (ALP)** and LDH levels correlate with tumor burden and prognosis. * **Gold Standard Investigation:** MRI for local staging; Biopsy for definitive diagnosis. * **Treatment:** Neoadjuvant chemotherapy → Limb salvage surgery → Adjuvant chemotherapy.

Q: A 6-year-old boy presents with right hip pain. Physical examination reveals a large mass near the iliac crest. Plain X-ray films show a large lytic lesion of the ilium. MRI studies indicate the tumor originates in the bone and extends into adjacent soft tissues. An incisional biopsy reveals a tumor composed of sheets of small, round, blue cells. What is the most likely diagnosis?

Ewing sarcoma. ### Explanation **Correct Answer: B. Ewing sarcoma** **Why it is correct:** Ewing sarcoma is the second most common primary malignant bone tumor in children and adolescents (typically aged 5–15 years). The clinical presentation of a young child with a large, lytic lesion in a flat bone (like the ilium) or the diaphysis of long bones is classic. The hallmark histopathological finding is **sheets of small, round, blue cells** (primitive neuroectodermal cells) which often contain glycogen (PAS positive). The MRI finding of a large soft tissue component ("extra-osseous extension") is highly characteristic of Ewing sarcoma. **Why the other options are incorrect:** * **A. Chondrosarcoma:** Typically occurs in older adults (40–60 years). Radiologically, it shows "popcorn" calcification or endosteal scalloping, not a purely lytic lesion in a 6-year-old. * **C. Giant cell tumor (GCT):** Usually occurs in young adults (20–40 years) after epiphyseal closure. It is located at the **epiphysis** and shows a "soap-bubble" appearance on X-ray. Histology shows multinucleated giant cells, not small round blue cells. * **D. Malignant fibrous histiocytoma (MFH):** Now often classified as pleomorphic undifferentiated sarcoma, it typically affects older adults and presents with a storiform (wheel-spoke) histological pattern rather than small round cells. **High-Yield Clinical Pearls for NEET-PG:** * **Genetics:** Associated with **t(11;22)** translocation involving the *EWS-FLI1* gene. * **Radiology:** Classic "onion-skin" periosteal reaction (though lytic destruction is also common). * **Markers:** CD99 (MIC2) positive. * **Differential for Small Round Blue Cell Tumors:** Ewing sarcoma, Lymphoma, Rhabdomyosarcoma, and Neuroblastoma. * **Site:** Most common site in the long bones is the **diaphysis**; most common flat bone is the **pelvis**.

Q: Which one of the following benign tumors can metastasize to the lung?

Chondroblastoma. **Explanation:** **Chondroblastoma** is a rare, benign cartilaginous tumor typically occurring in the **epiphysis** of long bones in young adults (skeletally immature). While histologically benign, it is well-known for its "locally aggressive" behavior. The correct answer is Chondroblastoma because it is one of the few benign bone tumors capable of producing **benign pulmonary implants (metastases)**. These lung lesions are histologically identical to the primary tumor and often grow very slowly or remain indolent, but they represent a classic exception to the rule that benign tumors do not metastasize. **Analysis of Incorrect Options:** * **A. Osteoid Osteoma:** A small, benign osteoblastic lesion characterized by a radiolucent nidus and nocturnal pain relieved by aspirin. It has no metastatic potential. * **B. Non-ossifying Fibroma (NOF):** A common, asymptomatic fibrous cortical defect usually found in children. Most undergo spontaneous regression and never metastasize. * **C. Hemangioma:** A benign vascular tumor, most commonly found in the vertebral bodies (showing a "corduroy cloth" or "jail-bar" appearance). It does not spread to distant organs. **High-Yield NEET-PG Pearls:** * **Benign tumors that metastasize to the lung:** The two most common examples are **Chondroblastoma** and **Giant Cell Tumor (GCT)** of the bone. * **Radiological Hallmark:** Chondroblastoma presents as an eccentric, lytic lesion in the epiphysis with a thin sclerotic rim. * **Histology:** Look for "Chicken-wire calcification" (calcification surrounding individual chondroblasts). * **Treatment:** Curettage and bone grafting; however, regular chest X-rays are recommended during follow-up to monitor for pulmonary nodules.

Q: A 10-year-old child presented with a swelling and mild pain around the knee joint along with muscle wasting. X-ray revealed a lesion arising from the epiphysis. Biopsy of the lesion was performed and HPE examination was done. What is the diagnosis?

Codman's Tumor. ### Explanation The correct diagnosis is **Codman’s Tumor**, also known as **Chondroblastoma**. **1. Why Codman’s Tumor is Correct:** The key to solving this case lies in the **age** and the **anatomical location**. Chondroblastoma is a rare, benign bone tumor that characteristically occurs in the **epiphysis** of long bones (most commonly the distal femur or proximal tibia) in children and adolescents (typically 10–20 years old). * **Clinical presentation:** Mild pain, swelling, and muscle wasting (due to disuse) are classic. * **Histopathology (HPE):** Though not detailed in the prompt, the characteristic finding is a "Chicken-wire" pattern of calcification and "Cobblestone" appearance of chondroblasts. **2. Why Other Options are Incorrect:** * **Chondrosarcoma:** Usually occurs in older adults (40–60 years) and typically involves the metaphysis or diaphysis of flat bones or long bones. It is rare in a 10-year-old. * **Osteosarcoma:** While common in this age group and location (around the knee), it primarily arises from the **metaphysis**, not the epiphysis. X-rays would show a Sunburst appearance or Codman’s triangle (periosteal reaction), which is different from Codman’s Tumor. * **Osteoblastoma:** This tumor most commonly involves the **vertebral column** (posterior elements) and typically presents in the metaphysis or diaphysis if found in long bones. **3. NEET-PG High-Yield Pearls:** * **Epiphyseal Tumors Mnemonic:** "Clear Cell Chondroblastoma" (Clear Cell Chondrosarcoma, Chondroblastoma, and Giant Cell Tumor—though GCT occurs after physeal closure). * **Radiology:** Chondroblastoma appears as a well-defined lytic lesion with a thin sclerotic rim in the epiphysis. * **Treatment:** Curettage and bone grafting.

Q: A child with a history of pain over lower extremities for a few months shows radiological evidence of osteosarcoma. What is the most common site of osteosarcoma?

Lower end of femur. **Explanation:** **Osteosarcoma** is the most common primary malignant bone tumor in children and adolescents. Its distribution is highly characteristic, primarily affecting the **metaphysis of long bones** where there is rapid longitudinal growth. **1. Why "Lower end of femur" is correct:** Approximately 50% of all osteosarcomas occur around the knee joint. The **lower end of the femur** is the single most common site (accounting for nearly 40% of cases), followed by the upper end of the tibia. This is because the growth plates in these areas are the most active in the human body, and the malignant transformation of osteoblasts is most likely to occur during periods of rapid bone turnover. **2. Why the other options are incorrect:** * **Upper end of femur (A):** While a common site for tumors like Ewing’s sarcoma or Chondrosarcoma in adults, it is less frequent than the knee region for Osteosarcoma. * **Lower end of fibula (C):** This is a rare site for primary bone tumors. The upper end of the fibula is more commonly involved than the lower end. * **Lower end of tibia (D):** While it can occur here, the incidence is significantly lower than the "around the knee" distribution (distal femur/proximal tibia). **Clinical Pearls for NEET-PG:** * **Age Group:** Bimodal distribution (10–20 years; second peak >60 years associated with Paget’s disease). * **Radiology:** Look for the **"Sunburst appearance"** (periosteal reaction) and **"Codman’s triangle"** (elevation of periosteum). * **Metastasis:** The most common site of distant spread is the **Lungs** (via hematogenous route). * **Biochemical Marker:** Serum **Alkaline Phosphatase (ALP)** is often elevated and serves as a marker for treatment response and recurrence. * **Genetic Association:** Strongly linked with mutations in the **Rb gene** (Retinoblastoma) and **TP53** (Li-Fraumeni syndrome).

Q: An 8-year-old boy presents with a swelling in the mid-thigh region. On examination, femoral thickening was found with Codman's triangle. On aspiration, greyish-white liquid was aspirated that showed atypical round cells with MIC-2 positivity. What is the most likely diagnosis?

Ewing's sarcoma. **Explanation:** The clinical presentation and immunohistochemistry point definitively to **Ewing’s Sarcoma**. 1. **Why Ewing’s Sarcoma is correct:** * **Age & Location:** It typically affects children and adolescents (5–15 years) and is the most common tumor of the **diaphysis** (mid-shaft) of long bones. * **Radiology:** While "onion-skin" appearance is classic, Ewing’s is highly aggressive and can present with a **Codman’s triangle** (periosteal elevation), indicating a rapidly growing lesion. * **Pathology:** The aspiration of "greyish-white liquid" (often mistaken for pus) containing **small round blue cells** is characteristic. * **Immunohistochemistry (IHC):** **MIC-2 (CD99)** positivity is the most specific marker for the Ewing’s family of tumors. 2. **Why other options are incorrect:** * **Osteosarcoma:** Usually occurs in the **metaphysis** (not mid-thigh/diaphysis). While it shows Codman’s triangle, IHC would show Osteocalcin positivity, not MIC-2. * **Pyogenic/Tubercular Osteomyelitis:** These can mimic Ewing’s clinically (fever, swelling) and radiologically. However, the presence of **atypical round cells** and **MIC-2 positivity** confirms a neoplastic process rather than an infection. **High-Yield Clinical Pearls for NEET-PG:** * **Translocation:** Associated with **t(11;22)** involving the EWS-FLI1 gene. * **PAS Stain:** Ewing’s cells are **PAS positive** due to cytoplasmic glycogen (unlike Lymphoma). * **Mimicry:** It is known as the "Great Mimicker" because it often presents with systemic symptoms like fever and elevated ESR, resembling osteomyelitis. * **Treatment:** It is highly radiosensitive; the standard protocol is Neoadjuvant Chemotherapy (VACA regimen) followed by surgery/radiotherapy.

Question 1

Which of the following statements about fibrous dysplasia is FALSE?

Accepted Answer

Biopsy is contraindicated.

Answer

It is associated with McCune-Albright syndrome.

Answer

It is associated with Mazabraud syndrome.

Answer

It can cause Shepherd's Crook deformity of the femur.

Question 2

Which of the following is an epiphyseal origin tumor?

Accepted Answer

Osteoclastoma

Answer

Osteogenic sarcoma

Answer

Ewing's sarcoma

Answer

Osteoblastoma

Question 3

An 8-year-old boy presented with pain in the arm. X-ray demonstrates an expansile lesion in the metaphysis of the upper humerus with breach of the overlying cortex. What is the most likely diagnosis?

Accepted Answer

Aneurysmal bone cyst

Answer

Unicameral bone cyst

Answer

Chondroblastoma

Answer

Osteoclastoma

Question 4

A 22-year-old male presents with a bony mass in the metaphyseal region of the right knee with a typical sun ray appearance. A CT scan of the chest reveals osteoblastic metastases. What is the most probable diagnosis?

Accepted Answer

Osteosarcoma

Answer

Chondrosarcoma

Answer

Ewing's sarcoma

Answer

Osteochondroma

Question 5

A 6-year-old boy presents with right hip pain. Physical examination reveals a large mass near the iliac crest. Plain X-ray films show a large lytic lesion of the ilium. MRI studies indicate the tumor originates in the bone and extends into adjacent soft tissues. An incisional biopsy reveals a tumor composed of sheets of small, round, blue cells. What is the most likely diagnosis?

Accepted Answer

Ewing sarcoma

Answer

Chondrosarcoma

Answer

Giant cell tumor of bone

Answer

Malignant fibrous histiocytoma

Question 6

Which one of the following benign tumors can metastasize to the lung?

Accepted Answer

Chondroblastoma

Answer

Osteoid osteoma

Answer

Non-ossifying fibroma

Answer

Hemangioma

Question 7

A 10-year-old child presented with a swelling and mild pain around the knee joint along with muscle wasting. X-ray revealed a lesion arising from the epiphysis. Biopsy of the lesion was performed and HPE examination was done. What is the diagnosis?

Accepted Answer

Codman's Tumor

Answer

Chondrosarcoma

Answer

Osteosarcoma

Answer

Osteoblastoma

Question 8

A child with a history of pain over lower extremities for a few months shows radiological evidence of osteosarcoma. What is the most common site of osteosarcoma?

Accepted Answer

Lower end of femur

Answer

Upper end of femur

Answer

Lower end of fibula

Answer

Lower end of tibia

Question 9

Arrange the following tumours according to increasing age group: Ewing's Sarcoma, Osteosarcoma, Osteoclastoma, Chondrosarcoma?

Accepted Answer

Ewing's Sarcoma, Osteosarcoma, Osteoclastoma, Chondrosarcoma

Answer

Osteosarcoma, Chondrosarcoma, Ewing's Sarcoma, Osteoclastoma

Answer

Osteoclastoma, Osteosarcoma, Chondrosarcoma, Ewing's Sarcoma

Answer

Chondrosarcoma, Ewing's Sarcoma, Osteoclastoma, Osteosarcoma

Question 10

An 8-year-old boy presents with a swelling in the mid-thigh region. On examination, femoral thickening was found with Codman's triangle. On aspiration, greyish-white liquid was aspirated that showed atypical round cells with MIC-2 positivity. What is the most likely diagnosis?

Accepted Answer

Ewing's sarcoma

Answer

Osteosarcoma

Answer

Tubercular osteomyelitis

Answer

Pyogenic osteomyelitis

Bone Tumors — MCQs

Bone Tumors — MCQs

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