Bone Tumors Practice Questions

Q: A 12-year-old boy presents with chronic knee pain for 2 years. The X-ray shows significant pathology. What is the probable diagnosis?

Osteosarcoma. ***Osteosarcoma*** - Most common **primary bone malignancy** in children and adolescents, typically affecting the **metaphyseal region** around the knee (distal femur, proximal tibia). - Classic X-ray features include **Codman's triangle**, **sunburst pattern**, and **mixed lytic-sclerotic lesions** in the metaphysis, which would explain the "significant pathology" mentioned. *Chronic osteomyelitis* - Usually presents with **systemic symptoms** like fever and elevated inflammatory markers, which are not mentioned in this case. - X-ray typically shows **sequestrum formation** and **involucrum** rather than the aggressive bone destruction pattern seen in malignancy. *Rickets* - Primarily affects **growth plates** and causes **bone deformities** like bowing of legs, not localized knee pain. - X-ray shows **osteopenia**, **coxa vara**, and **delayed ossification** rather than aggressive bone lesions. *Hyperparathyroidism* - Causes **generalized bone demineralization** and **brown tumors**, not localized aggressive lesions around the knee. - More commonly presents with **hypercalcemia symptoms** and affects multiple bones, particularly the **skull** and **long bones** diffusely.

Q: An Aneurysmal Bone Cyst (ABC) has a striking radiographic resemblance to which of the following conditions?

Chondroblastoma (CGC G). **Explanation:** The correct answer is **Chondroblastoma (Option A)**. **Why Chondroblastoma?** Aneurysmal Bone Cyst (ABC) is a benign, reactive, hypervascular bone lesion characterized by blood-filled cystic spaces. While ABC is typically an eccentric, "blow-out" lesion in the metaphysis, it is frequently associated with other primary bone tumors. This is known as a **Secondary ABC**. Approximately 20-25% of Chondroblastomas have an associated secondary ABC component. Radiographically, both can present as well-defined, lytic lesions. Furthermore, both tumors can cross the physis or involve the epiphysis (Chondroblastoma is classically epiphyseal), leading to a similar "soap-bubble" or expansile appearance on X-ray. **Why other options are incorrect:** * **Periapical Cemental Dysplasia (PCD):** This is a localized condition of the jaw (mandible) related to the teeth roots. It transitions from radiolucent to radiopaque over time and does not share the expansile, multi-loculated characteristics of ABC. * **Dentigerous Cyst:** An odontogenic cyst associated with the crown of an unerupted tooth. While cystic, its specific location and association with dentition make it radiographically distinct from ABC. * **Fibrous Dysplasia:** Classically presents with a "ground-glass" appearance due to the replacement of bone with fibrous tissue. It lacks the fluid-filled, expansile "blow-out" appearance seen in ABC. **High-Yield NEET-PG Pearls:** * **ABC Classic Sign:** "Fluid-fluid levels" on MRI (due to sedimentation of RBCs). * **ABC Location:** Metaphysis of long bones (most common). * **Chondroblastoma Classic Sign:** "Chicken-wire" calcification on histology. * **Secondary ABC:** Most commonly associated with **Giant Cell Tumor (GCT)**, followed by Osteoblastoma and Chondroblastoma.

Q: What is true about osteoclastoma?

Mononuclear cells are the malignant component.. **Explanation:** **Osteoclastoma**, also known as **Giant Cell Tumor (GCT)**, is a locally aggressive primary bone tumor. 1. **Why Option A is correct:** Histologically, GCT is characterized by a "dual cell population": multinucleated giant cells and **mononuclear stromal cells**. Crucially, the mononuclear cells are the **proliferative/neoplastic component** (the "true" tumor cells), while the giant cells are reactive osteoclasts formed by the recruitment of monocytes. 2. **Why the other options are incorrect:** * **Option B:** GCT typically occurs in young adults aged **20–40 years** (after epiphyseal closure). It is rare in children and the elderly. * **Option C:** The primary treatment is **surgical** (Intralesional curettage with bone grafting/cementing or wide excision). Radiotherapy is reserved for inoperable cases (e.g., spine) due to the risk of secondary malignant transformation (sarcoma). * **Option D:** GCT is a classic **epiphyseal** lesion that may extend into the metaphysis. It is never primarily diaphyseal. **High-Yield Clinical Pearls for NEET-PG:** * **Radiology:** Characterized by an eccentric, expansile, lytic lesion with a **"Soap Bubble" appearance**. It lacks a sclerotic rim. * **Location:** Most common around the knee (distal femur > proximal tibia) and distal radius. * **Pathology:** High expression of **RANK-L** by stromal cells. * **Pharmacology:** **Denosumab** (a RANK-L inhibitor) is used for unresectable or recurrent GCT. * **Complication:** Though benign, it can rarely cause "benign pulmonary metastasis."

Q: Which tumour most commonly metastasizes to bone in females?

Carcinoma breast. **Explanation:** The skeleton is the third most common site for metastatic disease, following the lung and liver. In females, **Carcinoma Breast** is the most common primary malignancy to metastasize to the bone, accounting for approximately 70% of all bone metastases in women. These lesions are typically **mixed (osteolytic and osteoblastic)** but are predominantly osteolytic. **Analysis of Options:** * **Carcinoma Breast (Correct):** Due to its high prevalence and the specific affinity of breast cancer cells for the bone marrow microenvironment (the "seed and soil" hypothesis), it is the leading cause of skeletal metastases in females. * **Carcinoma Lung:** This is the second most common cause in females. Notably, lung cancer is the most common primary to metastasize to the **distal bones** (acrometastasis), such as the hands and feet. * **Carcinoma Thyroid:** While thyroid cancer frequently spreads to the bone (often presenting as highly vascular, pulsatile expansile lytic lesions), its overall incidence is much lower than breast cancer. * **Carcinoma Ovary:** Ovarian cancer primarily spreads via local extension and peritoneal seeding; bone metastasis is relatively rare compared to the other options. **High-Yield Clinical Pearls for NEET-PG:** * **Overall Most Common:** In males, the most common primary is **Prostate Cancer** (typically osteoblastic lesions). * **Most Common Site:** The **spine** (specifically the thoracic spine) is the most frequent site for bone metastasis, followed by the pelvis and femur. * **Route of Spread:** Most metastases reach the spine via the **Batson’s venous plexus** (a valveless system). * **Pediatric Population:** **Neuroblastoma** is the most common primary tumor to metastasize to bone in children.

Q: A 20-year-old male presented with pain in the right shoulder region which aggravated with activity. On examination, a mass was felt in the right shoulder region which was warm and tender, had increased surface vascularity and a bruit was discernible over the mass. There was decreased range of motion of the right shoulder joint. X-ray and radionuclide scan were performed. The tumour was resected and sent for HPE examination. Which is the most likely diagnosis in the above scenario?

Osteosarcoma. ### Explanation The clinical presentation of a **20-year-old male** with a rapidly growing, painful mass in the proximal humerus (shoulder) that exhibits **increased surface vascularity, warmth, and a bruit** is a classic description of **Osteosarcoma**. **Why Osteosarcoma is correct:** Osteosarcoma is the most common primary malignant bone tumor in young adults. It typically occurs in the metaphyseal region of long bones (distal femur > proximal tibia > proximal humerus). The presence of a **bruit** and **increased local temperature** indicates a highly vascular, high-grade malignancy. These signs occur because the tumor induces rapid neo-angiogenesis to support its aggressive growth. **Why other options are incorrect:** * **Giant Cell Tumor (GCT):** While it occurs in young adults, it is typically **epiphyseal** and rarely presents with a bruit or significant surface vascularity unless it has undergone malignant transformation. * **Osteoid Osteoma:** This is a small lesion (<2 cm) characterized by nocturnal pain relieved by **aspirin/NSAIDs**. It does not present as a large, warm mass with a bruit. * **Osteoblastoma:** Often called a "giant osteoid osteoma," it typically involves the **vertebral column** (posterior elements). While it can be large, it lacks the aggressive vascular features and systemic signs of malignancy seen here. **Clinical Pearls for NEET-PG:** * **Radiology:** Look for "Sunray spiculation" (Sunburst appearance) and "Codman’s triangle" (periosteal elevation). * **Lab Findings:** Elevated **Serum Alkaline Phosphatase (ALP)** and LDH are important prognostic markers. * **Metastasis:** The most common site for distant spread is the **lungs** (via hematogenous route). * **HPE:** The hallmark is the presence of **malignant osteoid** (unmineralized bone) produced by neoplastic cells.

Q: According to the Enneking system, which of the following is NOT true regarding an active benign tumor?

Thick rim of reactive bone. The Enneking classification for benign bone tumors is based on clinical, radiographic, and histological behavior. It categorizes tumors into three stages: **Stage 1 (Latent)**, **Stage 2 (Active)**, and **Stage 3 (Aggressive)**. ### Why "Thick rim of reactive bone" is NOT true: An **Active (Stage 2)** tumor is growing steadily and is limited by a thin, often incomplete, rim of reactive bone or a fibrous capsule. A **thick, well-defined rim of reactive bone** (sclerotic rim) is the hallmark of a **Latent (Stage 1)** tumor, which is asymptomatic and does not grow. Therefore, Option C describes a Stage 1 tumor, not Stage 2. ### Analysis of other options: * **A. Intracapsular:** Active tumors remain confined within their natural capsule or the bone cortex. They do not breach the bone or extend into soft tissues (unlike Stage 3). * **B. Margin of reactive bone:** Active tumors are characterized by a thin, reactive zone. While it is present, it is not as robust or "thick" as in latent lesions. * **D. Extended curettage is treatment:** Because active tumors have a higher risk of recurrence than latent ones, simple curettage is often insufficient. **Extended curettage** (using adjuvants like phenol, liquid nitrogen, or a high-speed burr) is the standard treatment to ensure local control. ### High-Yield Clinical Pearls: * **Stage 1 (Latent):** Asymptomatic, thick sclerotic border (e.g., Non-ossifying fibroma). Treatment: Observation. * **Stage 2 (Active):** Symptomatic, thin reactive rim, expands the cortex (e.g., ABC, Osteoid Osteoma). Treatment: Extended curettage. * **Stage 3 (Aggressive):** Rapid growth, cortical breach, soft tissue extension (e.g., Giant Cell Tumor). Treatment: Wide excision or radical resection. * **Mnemonic:** Latent = **L**imited/Lazy; Active = **A**expanding; Aggressive = **A**ttacking.

Q: Which bone tumor arises from the area around the epiphyseal plate?

Chondroblastoma. **Explanation:** The correct answer is **Chondroblastoma**. This tumor is uniquely characterized by its anatomical location, as it is one of the few bone tumors that arises primarily in the **epiphysis** (or the apophysis) of long bones, specifically around the epiphyseal plate. **Why Chondroblastoma is correct:** Chondroblastoma is a rare, benign, but locally aggressive bone tumor. It typically occurs in the second decade of life (skeletally immature patients) before the growth plate closes. Its hallmark is its **epiphyseal location**, most commonly involving the distal femur, proximal tibia, or proximal humerus. **Analysis of Incorrect Options:** * **A. Osteosarcoma:** This is a malignant bone-forming tumor that typically arises in the **metaphysis** of long bones (the area of rapid bone turnover). * **B. Ewing’s Sarcoma:** This malignant tumor characteristically involves the **diaphysis** (shaft) of long bones or flat bones. It is known for its "onion-skin" periosteal reaction. * **C. Chondromyxoid Fibroma:** This is a rare benign tumor that usually arises in the **metaphysis**, though it may occasionally extend into the epiphysis. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Epiphyseal Tumors:** " **C**lear **G**iant **C**hondroblastoma" (**C**lear Cell Chondrosarcoma, **G**iant Cell Tumor, **C**hondroblastoma). * **Radiology:** Chondroblastoma appears as a well-defined lytic lesion with a thin sclerotic rim. * **Histology:** Look for the characteristic **"Chicken-wire calcification"** (calcification surrounding individual chondroblasts). * **Giant Cell Tumor (GCT):** While also epiphyseal, GCT occurs in **skeletally mature** individuals (after growth plate closure), whereas Chondroblastoma occurs in **skeletally immature** individuals.

Q: Which of the following is true for chondrosarcoma?

A slow growth rate is typical.. **Explanation:** Chondrosarcoma is a malignant tumor of cartilage-producing cells. Understanding its biological behavior is key to distinguishing it from other bone malignancies like Osteosarcoma. **1. Why Option D is Correct:** Chondrosarcomas are generally **slow-growing** tumors. They often present as an indolent, enlarging mass with dull, aching pain that has been present for months or even years. Because they are relatively resistant to chemotherapy and radiotherapy, the primary treatment is wide surgical excision. **2. Why the other options are incorrect:** * **Option A:** The peak incidence is in the **4th to 6th decades (40–60 years)**. It is rare in children. In contrast, Osteosarcoma and Ewing’s sarcoma typically affect the 10–20 year age group. * **Option B:** Most chondrosarcomas are **intramedullary (central)** lesions. While juxtacortical (periosteal) variants exist, they are much less common. * **Option C:** Chondrosarcoma primarily affects the **axial skeleton** (pelvis, ribs, and shoulder girdle) and the **proximal long bones** (femur and humerus). It rarely involves the small bones of the hands and feet; a cartilaginous lesion in the short bones is much more likely to be a benign Enchondroma. **High-Yield Clinical Pearls for NEET-PG:** * **Radiology:** Characterized by **"Popcorn calcification"** (stippled/flocculent calcification) and endosteal scalloping. * **Secondary Chondrosarcoma:** Can arise from pre-existing benign lesions like **Osteochondroma** (look for a cartilage cap >2 cm in adults) or **Enchondroma** (Ollier’s disease/Maffucci syndrome). * **Histology:** Features increased cellularity, nuclear atypia, and binucleated cells within a cartilaginous matrix.

Q: Which of the following bone tumors most commonly presents with lung secondaries and pneumothorax?

Osteosarcoma. **Explanation:** **Osteosarcoma** is the most common primary malignant bone tumor in children and adolescents. It has a high propensity for early hematogenous spread, specifically to the **lungs** (over 80% of metastases). A unique clinical hallmark of Osteosarcoma is that these pulmonary metastases are often subpleural and can undergo necrosis or cavitation, leading to the formation of a bronchopleural fistula. This results in **spontaneous pneumothorax**, a classic presentation often tested in NEET-PG. **Analysis of Incorrect Options:** * **B. Ewing’s Sarcoma:** While it also metastasizes to the lungs and other bones, it is less likely to cause a pneumothorax compared to the osteoid-forming Osteosarcoma. * **C. Osteoclastoma (Giant Cell Tumor):** This is generally a benign but locally aggressive tumor. While "benign pulmonary implants" can occur in about 2% of cases, they rarely lead to acute complications like pneumothorax. * **D. Chondroblastoma:** This is a benign bone tumor typically occurring in the epiphysis. It rarely metastasizes. **High-Yield Clinical Pearls for NEET-PG:** * **Radiology:** Osteosarcoma typically shows a "Sunray appearance" or "Codman’s triangle" on X-ray. * **Site:** Most common site is the distal femur (around the knee). * **Skip Lesions:** Osteosarcoma is known for "skip metastases" within the same bone. * **Alkaline Phosphatase:** Serum ALP levels are often elevated and serve as a marker for prognosis and treatment response. * **Treatment:** The standard of care is Neoadjuvant Chemotherapy (NACT) followed by limb-salvage surgery and postoperative chemotherapy.

Question 1

A 12-year-old boy presents with chronic knee pain for 2 years. The X-ray shows significant pathology. What is the probable diagnosis?

Accepted Answer

Osteosarcoma

Answer

Chronic osteomyelitis

Answer

Rickets

Answer

Hyperparathyroidism

Question 2

An Aneurysmal Bone Cyst (ABC) has a striking radiographic resemblance to which of the following conditions?

Accepted Answer

Chondroblastoma (CGC G)

Answer

Periapical Cemental Dysplasia (PCD)

Answer

Dentigerous cyst

Answer

Fibrous dysplasia

Question 3

Which of the following is true about non-ossifying fibroma of bone?

Accepted Answer

Histologically contains giant cells with areolar tissue and is a metaphyseal lesion

Answer

Present until the 3rd and 4th decade

Answer

Eccentric

Answer

Prominent sclerotic margin

Question 4

What is true about osteoclastoma?

Accepted Answer

Mononuclear cells are the malignant component.

Answer

It is common in the elderly.

Answer

Radiotherapy is the main modality of treatment.

Answer

It is a diaphyseal lesion.

Question 5

Which tumour most commonly metastasizes to bone in females?

Accepted Answer

Carcinoma breast

Answer

Carcinoma lung

Answer

Carcinoma thyroid

Answer

Carcinoma ovary

Question 6

A 20-year-old male presented with pain in the right shoulder region which aggravated with activity. On examination, a mass was felt in the right shoulder region which was warm and tender, had increased surface vascularity and a bruit was discernible over the mass. There was decreased range of motion of the right shoulder joint. X-ray and radionuclide scan were performed. The tumour was resected and sent for HPE examination. Which is the most likely diagnosis in the above scenario?

Accepted Answer

Osteosarcoma

Answer

Giant cell tumor

Answer

Osteoid osteoma

Answer

Osteoblastoma

Question 7

According to the Enneking system, which of the following is NOT true regarding an active benign tumor?

Accepted Answer

Thick rim of reactive bone

Answer

Intracapsular

Answer

Margin of reactive bone

Answer

Extended curettage is treatment

Question 8

Which bone tumor arises from the area around the epiphyseal plate?

Accepted Answer

Chondroblastoma

Answer

Osteosarcoma

Answer

Ewing's sarcoma

Answer

Chondromyxoid fibroma

Question 9

Which of the following is true for chondrosarcoma?

Accepted Answer

A slow growth rate is typical.

Answer

The peak incidence is between 10 and 20 years of age.

Answer

It usually presents as a juxtacortical lesion.

Answer

The short bones of the extremities are the most common site.

Question 10

Which of the following bone tumors most commonly presents with lung secondaries and pneumothorax?

Accepted Answer

Osteosarcoma

Answer

Ewing's sarcoma

Answer

Osteoclastoma

Answer

Chondroblastoma

Bone Tumors — MCQs

Bone Tumors — MCQs

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