Bone Tumors Practice Questions

Q: The X-ray of a knee in an adolescent boy is shown. What is the probable diagnosis?

Chondromyxoid fibroma. ***Chondromyxoid fibroma*** - Presents as an **eccentric metaphyseal lytic lesion** at the **proximal tibia** with **sclerotic margins** and **no calcification**, classic for this rare benign tumor in adolescents. - Typically affects the **metaphysis** of long bones, particularly around the knee, and shows a **well-defined cortical margin** without aggressive features. *Osteosarcoma* - Would demonstrate **aggressive periosteal reaction** with **Codman's triangle** or **sunburst pattern**, not seen in this case. - Commonly shows **osteoid matrix calcification** and **cortical destruction** with soft tissue extension, contrasting with the well-demarcated lesion shown. *Bone cyst with fracture* - Typically presents as a **central metaphyseal lesion** rather than eccentric, often with the **fallen fragment sign** after pathological fracture. - Shows **fluid-fluid levels** on MRI and lacks the **sclerotic rim** characteristic of chondromyxoid fibroma. *Osteitis fibrosa cystica* - Represents **brown tumors** associated with **hyperparathyroidism**, typically affecting multiple bones simultaneously. - Would present with elevated **serum calcium** and **parathyroid hormone levels**, along with **generalized bone demineralization** rather than an isolated lesion.

Q: What is the typical time period between the occurrence of osteosarcoma following radiation therapy?

10 years. **Explanation:** **Radiation-induced Osteosarcoma (RIS)** is a well-recognized late complication of radiotherapy. The correct answer is **10 years** because post-radiation sarcomas are characterized by a long latency period. 1. **Why 10 years is correct:** For a bone tumor to be classified as radiation-induced, it must meet the **Cahan’s Criteria**. One of the primary requirements is a significant latent period between irradiation and the development of the sarcoma. While the minimum threshold is often cited as 3–5 years, the **average (median) latency period is approximately 10 years**. This time is required for the accumulation of radiation-induced genetic mutations and malignant transformation of the bone cells. 2. **Why other options are incorrect:** * **1 Year (A):** This is too short. A tumor appearing within a year is likely a recurrence of the primary malignancy or a metastasis, rather than a new radiation-induced primary. * **3 & 5 Years (B & C):** While 3–5 years is considered the minimum "threshold" for diagnosis, it does not represent the "typical" or peak time of occurrence. NEET-PG questions usually seek the median or most common presentation period, which is a decade. **High-Yield Clinical Pearls for NEET-PG:** * **Cahan’s Criteria for RIS:** 1) Tumor must arise in the field of radiation; 2) Histology must be different from the primary tumor; 3) A long latent period (usually >5 years) must have elapsed. * **Most Common Type:** Osteosarcoma is the most common histological subtype of radiation-induced bone sarcoma. * **Prognosis:** Radiation-induced osteosarcomas generally have a **worse prognosis** than primary (de novo) osteosarcomas due to their central location and the difficulty of surgical resection in previously irradiated, fibrotic tissue. * **Common Sites:** Often seen following treatment for breast cancer (ribs/scapula) or retinoblastoma.

Q: What is the most common tumor of the vertebral spine in adults?

Secondary deposits. **Explanation:** The most common tumor of the vertebral spine in adults is **Secondary deposits (Metastatic disease)**. The spine is the most frequent site for skeletal metastasis due to its high content of red marrow and the presence of **Batson’s plexus** (a valveless venous network that allows retrograde spread of tumor cells from the pelvis, abdomen, and thorax). **Analysis of Options:** * **A. Secondary deposits (Correct):** Metastases outnumber primary bone tumors by a ratio of roughly 40:1. In adults, the most common primary sources are cancers of the **Prostate, Breast, Lung, and Kidney**. * **B. Multiple myeloma:** This is the most common **primary malignant** bone tumor in adults. While it frequently involves the spine, it is statistically less common than metastatic disease from non-marrow primaries. * **C. Lymphoma:** While it can involve the vertebrae (often presenting as an "Ivory vertebra"), it is significantly less common than metastases or myeloma. * **D. Hemangioma:** This is the most common **benign** tumor of the vertebral column. It is often an incidental finding on imaging, characterized by a "corduroy cloth" or "honeycomb" appearance. **NEET-PG High-Yield Pearls:** * **Most common site of spinal metastasis:** Thoracic spine (followed by lumbar). * **Earliest sign on X-ray:** Loss of the **pedicle** (the "Winking Owl" sign), as the pedicle lacks a cortex and is easily destroyed. * **Investigation of choice:** **MRI** is the most sensitive for early detection; **PET-CT** is used for staging. * **Osteoblastic vs. Osteolytic:** Prostate cancer typically causes osteoblastic (sclerotic) lesions, while Lung and Breast cancers often cause osteolytic lesions.

Q: Which of the following conditions is characterized by a "moth-eaten" bone appearance?

Multiple myeloma. **Explanation:** The **"moth-eaten"** pattern of bone destruction refers to a type of aggressive osteolysis characterized by multiple small, scattered, and poorly defined lucent areas. This pattern indicates a rapidly progressing lesion where the bone does not have sufficient time to mount a sclerotic defensive response. **Why Multiple Myeloma is correct:** Multiple Myeloma is a plasma cell dyscrasia that causes diffuse bone marrow infiltration. The malignant plasma cells secrete osteoclast-activating factors (like RANKL), leading to rapid bone resorption. Radiographically, this manifests as classic **"punched-out"** lesions or a diffuse **"moth-eaten"** appearance, particularly in the skull, spine, and pelvis. **Analysis of Incorrect Options:** * **A. Osteoid Osteoma:** Characterized by a small radiolucent **nidus** (less than 2 cm) surrounded by a dense zone of reactive sclerosis. It typically presents with nocturnal pain relieved by NSAIDs. * **C. Eosinophilic Granuloma:** Part of Langerhans Cell Histiocytosis (LCH). While it can cause bone destruction, it is classically associated with a **"punched-out"** appearance in the skull (without sclerosis) or a **"beveled edge"** appearance. * **D. Chondromyxoid Fibroma:** A rare benign cartilaginous tumor that typically presents as an eccentric, **soap-bubble**, or lobulated lucent lesion with a well-defined sclerotic rim, usually in the metaphysis. **NEET-PG High-Yield Pearls:** * **Moth-eaten/Permeative patterns** are seen in: Multiple Myeloma, Ewing’s Sarcoma, Osteosarcoma, and Metastatic neuroblastoma. * **Geographic destruction** (well-defined) suggests benign/slow-growing lesions (e.g., GCT). * **Multiple Myeloma** is the most common primary bone malignancy in adults. * **Key Lab Finding:** Bence-Jones proteins in urine and a "reversed" A:G ratio. Note that a **Bone Scan** is often negative in Multiple Myeloma because there is no osteoblastic activity.

Q: An X-ray of the proximal femur in a patient presenting with hip pain shows a specific deformity. What is this deformity?

Shepherd crook deformity. ***Shepherd crook deformity*** - Classic **coxa vara** deformity of the proximal femur seen in **fibrous dysplasia**, where the femoral neck bends downward resembling a shepherd's crook. - Results from **mechanical stress** on weakened bone filled with fibrous tissue, causing progressive **varus angulation** of the femoral neck. *Blade of grass deformity* - Characteristic radiological appearance of the **tibia** in **Paget's disease**, showing widened cortex and trabecular pattern. - Involves **long bones** like tibia and fibula, not typically the proximal femur as described in this case. *Chicken wire appearance* - Pathognomonic feature of **vertebral hemangiomas** showing coarse vertical trabeculae on lateral radiographs. - Specifically affects **vertebral bodies**, not the proximal femur or hip region. *Corduroy appearance* - Another radiological sign of **vertebral hemangiomas** seen on **frontal radiographs** showing vertical striations. - Limited to **spinal vertebrae** and does not involve the femoral neck or hip joint area.

Q: Which of the following is NOT a common site of primary bone metastasis?

Brain. **Explanation:** The correct answer is **Brain**. Primary bone metastasis refers to cancers that frequently spread to the skeletal system. The brain is not a common primary source for bone metastasis; in fact, primary brain tumors (like Gliomas) rarely metastasize outside the central nervous system because they lack a lymphatic drainage system and patients often succumb to the local effects of the tumor before systemic spread occurs. **Analysis of Options:** * **Breast (Option A):** This is the most common primary site for bone metastasis in **females**. These lesions are typically **mixed** (osteolytic and osteoblastic). * **Prostate (Option B):** This is the most common primary site in **males**. It is classically associated with **osteoblastic** (sclerotic) lesions due to the secretion of prostate-specific acid phosphatase. * **Kidney (Option D):** Renal Cell Carcinoma (RCC) frequently spreads to the bone, typically causing highly vascular, **purely osteolytic** lesions. **NEET-PG High-Yield Pearls:** * **Mnemonic for Bone Metastasis:** "**B**e **P**olite **L**ove **K**ids **T**erribly" (**B**reast, **P**rostate, **L**ung, **K**idney, **T**hyroid). * **Most common site of bone metastasis:** The **spine** (specifically the thoracic spine) via the **Batson venous plexus**. * **Lesion Types:** * **Osteoblastic:** Prostate (most common), Carcinoid, Small cell lung cancer. * **Osteolytic:** Kidney, Thyroid, Lung (NSCLC). * **Mixed:** Breast. * **Investigation of Choice:** **99mTc-MDP Bone Scan** is the most sensitive screening tool (except for Multiple Myeloma and purely lytic lesions where X-rays or MRI are preferred).

Q: All of the following statements regarding Ewing's sarcoma are true EXCEPT?

Flexner-Wintersteiner rosettes are seen.. ### Explanation **Ewing’s Sarcoma** is a highly malignant, small round blue cell tumor typically affecting children and adolescents. #### Why Option D is the Correct Answer (The "Except" Statement) **Flexner-Wintersteiner rosettes** are characteristic of **Retinoblastoma** (and occasionally Pineoblastoma). In Ewing’s sarcoma, the classic histological finding is **Homer-Wright rosettes**, where tumor cells are arranged around a central fibrillar area. Both are "small round blue cell tumors," but the type of rosette is a critical distinguishing factor for exams. #### Analysis of Incorrect Options (True Statements) * **A. Common location is the diaphysis:** Unlike Osteosarcoma (metaphysis), Ewing’s sarcoma is the most common primary bone tumor to arise in the **diaphysis** (shaft) of long bones (femur, tibia) and flat bones (pelvis). * **B. Symptoms resemble osteomyelitis:** Patients often present with systemic symptoms like fever, elevated ESR, leukocytosis, and a painful, warm swelling. This mimics an infection, making osteomyelitis the primary differential diagnosis. * **C. Translocation t(11;22):** This is the pathognomonic genetic hallmark, found in >90% of cases. It results in the **EWS-FLI1** fusion gene. #### NEET-PG High-Yield Pearls * **Radiology:** Classic **"onion-skin"** periosteal reaction (due to layers of new bone formation). * **Origin:** Derived from primitive neuroectodermal cells (mesenchymal stem cells). * **PAS Staining:** Tumor cells are **PAS positive** because they contain glycogen (unlike Lymphoma). * **Marker:** **CD99** (MIC2) is a highly sensitive membrane marker for Ewing’s sarcoma. * **Treatment:** It is highly radiosensitive; however, the standard of care is a combination of chemotherapy and surgery (VAC regimen: Vincristine, Adriamycin, Cyclophosphamide).

Q: What is the most probable diagnosis based on the X-ray findings in a 20-year-old female presenting with knee swelling?

Osteosarcoma. ***Osteosarcoma*** - Most common **primary bone malignancy** in young adults (10-25 years), typically affecting the **metaphysis** of long bones around the knee (distal femur, proximal tibia). - Classic X-ray features include **mixed lytic-sclerotic lesions**, **Codman's triangle** (periosteal elevation), and **sunburst pattern** of new bone formation. *Osteoclastoma* - Also known as **giant cell tumor**, typically occurs in patients aged **20-40 years** but has a predilection for the **epiphysis** rather than metaphysis. - X-ray shows **purely lytic lesions** with well-defined margins and **soap bubble appearance**, lacking the aggressive mixed pattern seen in osteosarcoma. *Osteochondroma* - Most common **benign bone tumor**, usually presents as an **asymptomatic bony projection** rather than swelling. - X-ray shows a **pedunculated or sessile bony outgrowth** with **cartilaginous cap**, not the destructive mixed lytic-sclerotic pattern typical of malignant tumors. *None of the above* - Given the patient's age (**20 years**), location (**knee**), and typical X-ray findings described, osteosarcoma fits the classic presentation. - The **demographic profile** and **radiological characteristics** strongly support a specific diagnosis rather than an atypical presentation.

Q: Expansile pulsating secondary metastasis is a feature of which of the following?

Renal cell carcinoma. **Explanation:** The correct answer is **Renal cell carcinoma (RCC)**. **1. Why Renal Cell Carcinoma is correct:** Expansile, osteolytic, and **pulsating** skeletal metastases are characteristic of highly vascular tumors. RCC is the most common cause of such lesions. The "pulsatile" nature occurs because these metastases are extremely hypervascular; the high blood flow within the lesion transmits the arterial pulse, which can sometimes be felt on clinical palpation or heard as a bruit. On imaging, these appear as "blow-out" lytic lesions. **2. Why the other options are incorrect:** * **Basal Cell Carcinoma (BCC):** BCC is a locally invasive skin cancer that rarely metastasizes to distant organs or bones. * **Osteogenic Sarcoma (Osteosarcoma):** This is a primary bone tumor, not a secondary metastasis. While it is vascular, it typically presents with bone formation (osteoid) and a "sunburst" periosteal reaction rather than expansile pulsatile secondary deposits. * **Carcinoma of the Prostate:** This is the classic cause of **osteoblastic (sclerotic)** metastases. These lesions are dense and radio-opaque, not expansile or pulsatile. **3. High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Pulsatile Bone Metastases:** **"R-T-C"** (Renal cell carcinoma, Thyroid carcinoma—specifically follicular variety, and Choriocarcinoma). * **Most common source of bone metastasis in males:** Prostate cancer. * **Most common source of bone metastasis in females:** Breast cancer. * **Most common site for bone metastasis:** Spine (Vertebral column). * **Imaging of choice:** While Bone Scan (Technetium-99m MDP) is used for screening, it may show a **"cold lesion"** in pure lytic tumors like RCC or Multiple Myeloma. MRI is more sensitive for detecting early marrow involvement.

Q: A 22-year-old male presents with pain and swelling over the distal radius. X-ray shows an expansile lytic lesion in the metaphysis. Fine needle aspiration (FNA) reveals a bloody aspirate with hemosiderin-laden macrophages. What is the most likely diagnosis?

Aneurysmal bone cyst. ***Aneurysmal bone cyst*** - Aneurasymal bone cysts (ABCs) typically present as **expansile, soap-bubble lytic lesions** located in the **metaphysis** of long bones in patients under 30. - Diagnostic aspiration characteristically yields a **bloody fluid** and cytology shows **hemosiderin-laden macrophages** within fibrous septa, rather than solid tumor tissue. *Giant cell tumor* - Although GCT is a lytic lesion in young adults, it is primarily located in the **epiphysis** extending to the articular surface, not restricted to the metaphysis. - Histopathology would show a high concentration of **multinucleated giant cells** and mononuclear stromal cells rather than predominantly blood and macrophages. *Chondroblastoma* - Chondroblastomas are almost exclusively found in the **epiphysis** or apophysis of long bones, making a purely metaphyseal location unlikely. - Characteristic biopsy findings include **chondroblasts** and a unique **"chicken-wire" calcification** pattern, which are absent in this presentation. *Osteosarcoma* - Osteosarcoma usually presents with a mix of lytic and **sclerotic areas** accompanied by aggressive periosteal reactions like the **Codman triangle**. - Fine needle aspiration would show **pleomorphic malignant cells** and the presence of **neoplastic osteoid**, which contrasts with the benign bloody aspirate typical of an ABC.

Question 1

The X-ray of a knee in an adolescent boy is shown. What is the probable diagnosis?

Accepted Answer

Chondromyxoid fibroma

Answer

Osteosarcoma

Answer

Bone cyst with fracture

Answer

Osteitis fibrosa cystica

Question 2

What is the typical time period between the occurrence of osteosarcoma following radiation therapy?

Accepted Answer

10 years

Answer

1 year

Answer

3 years

Answer

5 years

Question 3

What is the most common tumor of the vertebral spine in adults?

Accepted Answer

Secondary deposits

Answer

Multiple myeloma

Answer

Lymphoma

Answer

Hemangioma

Question 4

Which of the following conditions is characterized by a "moth-eaten" bone appearance?

Accepted Answer

Multiple myeloma

Answer

Osteoid osteoma

Answer

Eosinophilic granuloma

Answer

Chondromyxoid fibroma

Question 5

An X-ray of the proximal femur in a patient presenting with hip pain shows a specific deformity. What is this deformity?

Accepted Answer

Shepherd crook deformity

Answer

Blade of grass deformity

Answer

Chicken wire appearance

Answer

Corduroy appearance

Question 6

Which of the following is NOT a common site of primary bone metastasis?

Accepted Answer

Brain

Answer

Breast

Answer

Prostate

Answer

Kidney

Question 7

All of the following statements regarding Ewing's sarcoma are true EXCEPT?

Accepted Answer

Flexner-Wintersteiner rosettes are seen.

Answer

Common location is the diaphysis of long bones.

Answer

Symptoms resemble osteomyelitis.

Answer

Translocation t(11;22) is classical.

Question 8

What is the most probable diagnosis based on the X-ray findings in a 20-year-old female presenting with knee swelling?

Accepted Answer

Osteosarcoma

Answer

Osteoclastoma

Answer

Osteochondroma

Answer

None of the above

Question 9

Expansile pulsating secondary metastasis is a feature of which of the following?

Accepted Answer

Renal cell carcinoma

Answer

Basal cell carcinoma

Answer

Osteogenic sarcoma

Answer

Carcinoma of the prostate

Question 10

A 22-year-old male presents with pain and swelling over the distal radius. X-ray shows an expansile lytic lesion in the metaphysis. Fine needle aspiration (FNA) reveals a bloody aspirate with hemosiderin-laden macrophages. What is the most likely diagnosis?

Accepted Answer

Aneurysmal bone cyst

Answer

Giant cell tumor

Answer

Chondroblastoma

Answer

Osteosarcoma

Bone Tumors — MCQs

Bone Tumors — MCQs

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