Bone Tumors Practice Questions

Q: What is the typical age group affected by osteoclastoma?

20-40 years. **Explanation:** **Osteoclastoma**, also known as **Giant Cell Tumor (GCT)** of the bone, is a unique primary bone tumor characterized by its occurrence after the closure of the epiphyseal plate. 1. **Why 20-40 years is correct:** GCT typically affects young adults in the **3rd and 4th decades** of life. The hallmark of this tumor is that it occurs in the **epiphysis** of long bones (most commonly the distal femur and proximal tibia) only after the growth plates have fused. It is rare in children and the elderly. 2. **Why other options are incorrect:** * **5-10 years:** This age group is more characteristic of **Ewing’s Sarcoma** or simple bone cysts. * **10-20 years:** This is the peak incidence for **Osteosarcoma** and **Ewing’s Sarcoma**, which primarily affect the adolescent skeleton during growth spurts. * **>50 years:** Bone tumors in this age group are most likely to be **Metastatic bone disease** or **Multiple Myeloma**. **High-Yield Clinical Pearls for NEET-PG:** * **Radiological Appearance:** Characterized by a **"Soap Bubble" appearance** (eccentric, expansile, lytic lesion). * **Location:** It is a truly **epiphyseal** tumor that may extend into the metaphysis. * **Pathology:** Shows multinucleated giant cells (osteoclast-like) scattered among mononuclear stromal cells (the actual neoplastic component). * **Behavior:** It is "locally aggressive" but usually benign. However, it can rarely metastasize to the lungs (benign pulmonary metastasis). * **Treatment:** The treatment of choice is **extended curettage** with the use of adjuvants (like liquid nitrogen or phenol) and bone grafting/bone cement (PMMA).

Q: All of the following investigations are needed for the diagnosis of osteosarcoma, except?

Bone marrow biopsy. **Explanation:** The diagnosis and staging of **Osteosarcoma** (the most common primary malignant bone tumor in children and adolescents) focus on assessing the local extent of the primary lesion and identifying distant metastases. **Why Bone Marrow Biopsy is the Correct Answer:** Bone marrow biopsy is **not** a routine investigation for osteosarcoma. Osteosarcoma typically spreads via the **hematogenous route**, primarily to the lungs and other bones. Unlike Small Round Blue Cell Tumors (such as **Ewing’s Sarcoma** or Neuroblastoma), osteosarcoma does not characteristically involve the bone marrow. Therefore, a marrow biopsy does not provide diagnostic or staging utility. **Analysis of Other Options:** * **MRI of the Femur (Local Staging):** This is the gold standard for evaluating the local extent of the tumor. It assesses marrow involvement, soft tissue extension, and the presence of **"skip lesions"** (secondary tumor foci within the same bone). * **CT Chest (Systemic Staging):** The lungs are the most common site of metastasis. A high-resolution CT chest is mandatory to detect pulmonary nodules, which may be missed on a standard X-ray. * **Bone Scan (Systemic Staging):** A Technetium-99m MDP bone scan is used to identify distant skeletal metastases or polyostotic involvement. **Clinical Pearls for NEET-PG:** * **Most common site:** Distal femur (around the knee). * **Radiological hallmarks:** Codman’s triangle and Sunburst appearance. * **Biopsy:** Always the definitive diagnostic step, but it must be planned by the surgeon performing the limb salvage surgery to avoid tract contamination. * **Metastasis:** Lung is the most common site; "Skip lesions" are a poor prognostic factor.

Q: In a young boy, an X-ray of the upper end of the tibia shows a lytic lesion. Which of the following is the least likely diagnosis?

Giant cell tumor. ### Explanation The correct answer is **Giant Cell Tumor (GCT)**. The primary reason GCT is the least likely diagnosis in this scenario is the **age of the patient**. **1. Why Giant Cell Tumor is the least likely:** GCT is a tumor of the **skeletally mature** population, typically occurring between **20 and 40 years of age**. It occurs only after the epiphyseal plate has closed. In a "young boy" (skeletally immature), the physis acts as a barrier, making GCT extremely rare. Furthermore, GCT is characteristically **epiphyseal**, whereas most childhood lytic lesions are metaphyseal. **2. Analysis of other options:** * **Osteosarcoma:** This is the most common primary malignant bone tumor in children and adolescents. It frequently presents as a lytic or mixed lytic-blastic lesion in the **metaphysis** of the upper tibia. * **Solitary Bone Cyst (SBC):** These are common benign, fluid-filled lytic lesions found in children, typically located in the metaphysis of long bones like the proximal humerus or tibia. * **Tuberculosis (Cystic TB):** Skeletal TB can present as a localized lytic lesion (Brodie’s abscess mimic) in children, especially in endemic regions like India. It can occur at any age. **Clinical Pearls for NEET-PG:** * **GCT Key Features:** Epiphyseal location, "Soap-bubble" appearance, eccentric expansion, and occurs after physeal closure. * **Common Lytic Lesions in Children (FEEL):** **F**ibrous dysplasia/Fibrous cortical defect, **E**nchondroma/Eosinophilic granuloma, **E**neurysmal bone cyst, **L**ower-grade infections/Simple bone cyst. * **Location Rule:** If the physis is open, think Metaphyseal (Osteosarcoma, SBC); if the physis is closed, think Epiphyseal (GCT).

Q: Which of the following tumors occurs in the epiphysis?

Chondroblastoma. **Explanation:** The location of a bone tumor relative to the growth plate (epiphysis, metaphysis, or diaphysis) is a high-yield diagnostic hallmark in orthopaedics. **Why Chondroblastoma is correct:** **Chondroblastoma** (also known as Codman’s tumor) is a rare, benign bone tumor that characteristically occurs in the **epiphysis** of long bones (commonly the distal femur or proximal tibia) in skeletally immature patients (children and adolescents). On histology, it shows a "chicken-wire" calcification pattern. **Analysis of Incorrect Options:** * **Osteoclastoma (Giant Cell Tumor):** While GCT involves the epiphysis, it typically occurs in **skeletally mature** adults after the growth plate has closed. It is described as "subarticular," starting in the metaphysis and extending into the epiphysis. * **Osteochondroma:** This is the most common benign bone tumor. It occurs in the **metaphysis** and is characterized by a pedunculated or sessile bony outgrowth covered by a cartilage cap. * **Ewing’s Sarcoma:** This is a highly malignant small round blue cell tumor that typically arises in the **diaphysis** (shaft) of long bones in children, often presenting with an "onion-skin" periosteal reaction. **NEET-PG High-Yield Pearls:** * **Epiphyseal Tumors:** Remember the mnemonic **"C-G"** (Chondroblastoma and Giant Cell Tumor). * **Diaphyseal Tumors:** Remember **"E-M-O"** (Ewing’s sarcoma, Multiple myeloma, Osteoid osteoma). * **Metaphyseal Tumors:** Most common site for tumors like Osteosarcoma and Osteochondroma. * **Chondroblastoma Key Sign:** "Chicken-wire" calcification. * **GCT Key Sign:** "Soap-bubble" appearance on X-ray.

Q: Mafucci syndrome is characterized by which of the following combinations?

Multiple enchondromas with soft tissue hemangiomas. **Explanation:** **Maffucci Syndrome** is a rare genetic disorder characterized by the coexistence of **multiple enchondromas** (benign cartilage-forming tumors) and **soft tissue hemangiomas** (usually cavernous type). The underlying pathophysiology involves somatic mutations in the **IDH1 or IDH2 genes**. 1. **Why Option B is correct:** The hallmark of Maffucci syndrome is the combination of skeletal enchondromatosis and vascular lesions (hemangiomas). These hemangiomas often present as soft, blue-colored subcutaneous nodules and may contain **phleboliths** (calcified thrombi) visible on X-ray. 2. **Why other options are wrong:** * **Option A & C:** Multiple osteochondromas are characteristic of **Hereditary Multiple Exostoses (HME)**, not Maffucci syndrome. Osteochondromas are bone-capped surface projections, whereas enchondromas are intramedullary. * **Option D:** Multiple hemangiomas alone do not constitute Maffucci syndrome; the skeletal component (enchondromas) is a mandatory diagnostic criterion. **High-Yield Clinical Pearls for NEET-PG:** * **Ollier Disease:** Characterized by multiple enchondromas *without* hemangiomas. * **Malignant Transformation:** Maffucci syndrome carries a significantly higher risk of malignancy compared to Ollier disease. There is a **15–30% risk of Chondrosarcoma** and an increased risk of visceral malignancies (e.g., ovarian granulosa cell tumors, pancreatic adenocarcinoma). * **Radiological Sign:** On X-ray, enchondromas show "popcorn calcification" or "rings and arcs," while soft tissues may show phleboliths. * **Distribution:** Usually asymmetrical and can lead to severe skeletal deformities and pathological fractures.

Q: What is the most common site of osteogenic sarcoma?

Knee joint. **Explanation:** **Osteogenic Sarcoma (Osteosarcoma)** is the most common primary malignant bone tumor in children and adolescents. The correct answer is the **Knee joint** because this tumor characteristically involves the **metaphysis of long bones** where there is the most rapid longitudinal growth. 1. **Why the Knee Joint is Correct:** Approximately 50-60% of all osteosarcomas occur around the knee. Specifically, the **distal femur** (most common site overall) and the **proximal tibia** are the primary locations. These areas have the highest rate of epiphyseal growth and cellular turnover, which predisposes them to malignant transformation during the adolescent growth spurt. 2. **Why Other Options are Incorrect:** * **Wrist joint:** While osteosarcoma can occur in the distal radius, it is significantly less common than the knee. * **Jaw bone:** Mandibular osteosarcoma typically occurs in an older age group (3rd-4th decade) and represents a small fraction of cases. * **Shoulder joint:** The **proximal humerus** is the third most common site for osteosarcoma, but it lags far behind the knee in frequency. **High-Yield Clinical Pearls for NEET-PG:** * **Age Distribution:** Bimodal (10–20 years; and >60 years associated with Paget’s disease). * **Radiological Signs:** Look for the **"Sunburst appearance"** (spicules of bone formation) and **"Codman’s triangle"** (periosteal elevation). * **Laboratory:** Elevated **Serum Alkaline Phosphatase (ALP)** and LDH are important prognostic markers. * **Metastasis:** The most common site of distant spread is the **Lungs** (via hematogenous route). * **Genetic Association:** Strongly linked with mutations in the **Rb gene** (Retinoblastoma) and **TP53** (Li-Fraumeni syndrome).

Q: What is the most common site of occurrence for chondroblastoma?

Proximal tibia. **Explanation:** **Chondroblastoma** (also known as Codman’s tumor) is a rare, benign, but locally aggressive bone tumor. The defining characteristic of this tumor is its **epiphyseal** location in skeletally immature patients (before the growth plate closes). 1. **Why Proximal Tibia is Correct:** Chondroblastoma most frequently occurs in the long bones. The **proximal humerus** is historically cited as a classic site, but statistically, the **femur (distal)** and the **proximal tibia** are the most common sites of occurrence. Among the options provided, the proximal tibia represents a primary site for this epiphyseal lesion. 2. **Why Other Options are Incorrect:** * **Pelvis:** While it can occur in the triradiate cartilage of the pelvis, this is far less common than long bone involvement. * **Femur:** The femur is a very common site (distal femur), but in many standardized MCQ formats, if both are not listed as a combined "around the knee" option, the proximal tibia is a frequently tested correct answer. * **Ribs:** Chondroblastoma is exceptionally rare in the ribs; tumors like chondrosarcoma or osteochondroma are more common in the thoracic cage. **Clinical Pearls for NEET-PG:** * **Age Group:** Typically occurs in the 2nd decade (10–20 years). * **Radiology:** A well-defined **lytic lesion** in the **epiphysis**. It may show a "sclerotic rim." * **Histology:** Characterized by "Chicken-wire calcification" (calcification surrounding individual chondroblasts). * **Key Differential:** Giant Cell Tumor (GCT), but GCT occurs *after* physeal closure, whereas Chondroblastoma occurs *before*. * **Treatment:** Curettage and bone grafting.

Q: Bony metastasis is common with all of the following cancers except:

Testicular cancer. **Explanation:** The skeleton is the third most common site for metastatic disease. The primary cancers that most frequently metastasize to the bone can be remembered by the popular mnemonic **"BLT with a Kosher Pickle"** (Breast, Lung, Thyroid, Kidney, Prostate). **Why Testicular Cancer is the Correct Answer:** Testicular cancers (especially germ cell tumors) primarily spread via the lymphatic system to the retroperitoneal lymph nodes. While advanced stages can involve visceral organs like the lungs or liver, **bony metastasis is rare** in testicular cancer compared to the other options listed. **Analysis of Incorrect Options:** * **Breast Cancer (A):** The most common source of bony metastasis in females. It typically produces **mixed** (osteolytic and osteoblastic) lesions. * **Lung Cancer (B):** A very common source of bone metastasis in both genders. It is the most common cause of **osteolytic** metastases and is unique for its tendency to metastasize to the small bones of the hands and feet (acrometastasis). * **Prostate Cancer (D):** The most common source of bony metastasis in males. It characteristically produces **osteoblastic** (sclerotic) lesions due to the secretion of prostate-specific acid phosphatase and other factors. **NEET-PG High-Yield Pearls:** 1. **Most common site of bone metastasis:** Spine (specifically the thoracic spine). 2. **Batson’s Plexus:** The valveless vertebral venous plexus that allows retrograde spread of cancer (especially prostate) to the spine without passing through the lungs. 3. **Radiological sign:** The "Winking Owl Sign" on a spinal X-ray indicates destruction of a pedicle by metastasis. 4. **Osteoblastic vs. Osteolytic:** Prostate is purely blastic; Lung, Kidney, and Thyroid are typically lytic; Breast is mixed.

Q: Which of the following is not a benign bone tumor?

Chordoma. **Explanation:** The correct answer is **D. Chordoma**. A **Chordoma** is a rare, slow-growing, but **malignant** primary bone tumor. It arises from the remnants of the primitive **notochord**. It is locally aggressive and has a high rate of recurrence. Clinically, it most commonly occurs at the ends of the spinal column: the **sacrococcygeal region** (most common) and the **spheno-occipital (clivus) region**. On imaging, it typically presents as a midline destructive lesion with associated soft tissue mass and calcification. **Why the other options are incorrect:** * **Osteoid osteoma (A):** A common benign osteoblastic tumor characterized by a small radiolucent **nidus** (less than 2 cm) surrounded by reactive sclerosis. It classically presents with nocturnal pain relieved by NSAIDs/Aspirin. * **Chondroma (B) & Enchondroma (C):** These are benign cartilaginous tumors. An enchondroma is a chondroma located within the medullary cavity (most common in the small bones of the hands and feet). While they have a small risk of malignant transformation into chondrosarcoma (especially in syndromes like Ollier disease), they are inherently benign. **High-Yield NEET-PG Pearls:** * **Chordoma Hallmark:** Histopathology shows characteristic **Physaliphorous cells** (large, vacuolated cells with "soap bubble" appearance). * **Age Group:** Chordomas typically occur in patients aged 40–70 years. * **Treatment:** They are relatively radioresistant; the primary treatment is wide surgical excision. * **Commonest Benign Bone Tumor:** Osteochondroma. * **Commonest Malignant Bone Tumor:** Osteosarcoma (Primary) or Metastasis (Overall).

Question 1

What is the typical age group affected by osteoclastoma?

Accepted Answer

20-40 years

Answer

5-10 years

Answer

10-20 years

Answer

>50 years

Question 2

All of the following investigations are needed for the diagnosis of osteosarcoma, except?

Accepted Answer

Bone marrow biopsy

Answer

MRI of femur

Answer

Bone scan

Answer

CT chest

Question 3

In a young boy, an X-ray of the upper end of the tibia shows a lytic lesion. Which of the following is the least likely diagnosis?

Accepted Answer

Giant cell tumor

Answer

Osteosarcoma

Answer

Solitary bone cyst

Answer

Tuberculosis

Question 4

Which of the following tumors occurs in the epiphysis?

Accepted Answer

Chondroblastoma

Answer

Osteoclastoma

Answer

Osteochondroma

Answer

Ewing's sarcoma

Question 5

Mafucci syndrome is characterized by which of the following combinations?

Accepted Answer

Multiple enchondromas with soft tissue hemangiomas

Answer

Multiple osteochondromas

Answer

Multiple osteochondromas with soft tissue hemangiomas

Answer

Multiple hemangiomas

Question 6

What is the most common site of osteogenic sarcoma?

Accepted Answer

Knee joint

Answer

Wrist joint

Answer

Jaw bone

Answer

Shoulder joint

Question 7

A 60-year-old male presents with bone pain, vertebral collapse, and fracture of the pelvis. What is the probable diagnosis?

Accepted Answer

Secondaries (metastatic disease)

Answer

Multiple myeloma

Answer

Tuberculosis (TB)

Answer

Hemangioma of bone

Question 8

What is the most common site of occurrence for chondroblastoma?

Accepted Answer

Proximal tibia

Answer

Pelvis

Answer

Femur

Answer

Ribs

Question 9

Bony metastasis is common with all of the following cancers except:

Accepted Answer

Testicular cancer

Answer

Breast cancer

Answer

Lung cancer

Answer

Prostate cancer

Question 10

Which of the following is not a benign bone tumor?

Accepted Answer

Chordoma

Answer

Osteoid osteoma

Answer

Chondroma

Answer

Enchondroma

Bone Tumors — MCQs

Bone Tumors — MCQs

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