Bone Tumors Practice Questions

Q: Which of the following tumors is the most chemoresistant?

Malignant fibrous histiocytoma. ### Explanation The correct answer is **Malignant Fibrous Histiocytoma (MFH)**, now more commonly classified as **Undifferentiated Pleomorphic Sarcoma (UPS)**. #### 1. Why Malignant Fibrous Histiocytoma is Correct MFH/UPS is a high-grade soft tissue and bone sarcoma characterized by extreme cellular pleomorphism and a lack of a specific line of differentiation. Among the options provided, it is notorious for its **poor response to chemotherapy**. While multi-agent chemotherapy (like Doxorubicin and Ifosfamide) is often used as an adjuvant to surgery, the survival benefit is significantly lower compared to other sarcomas. Its primary treatment remains wide surgical excision, as it is considered relatively **chemoresistant and radioresistant**. #### 2. Why the Other Options are Incorrect * **Osteosarcoma:** This is a **chemosensitive** tumor. The introduction of neoadjuvant chemotherapy (MAP protocol: Methotrexate, Adriamycin, Platinum) revolutionized its prognosis, increasing the 5-year survival rate from 20% to nearly 70%. * **Embryonal Rhabdomyosarcoma:** This is highly **chemosensitive**. Chemotherapy is a cornerstone of management (VAC regimen: Vincristine, Actinomycin-D, Cyclophosphamide), often leading to significant tumor shrinkage. * **Synovial Sarcoma:** While aggressive, it is considered **moderately chemosensitive**, particularly to Ifosfamide-based regimens, unlike the relative resistance seen in MFH. #### 3. NEET-PG High-Yield Pearls * **Most Radiosensitive Bone Tumor:** Ewing’s Sarcoma. * **Most Chemosensitive Bone Tumor:** Ewing’s Sarcoma (followed by Osteosarcoma). * **Tumor with "Storiform" Pattern on Histology:** Malignant Fibrous Histiocytoma. * **Sunray Appearance/Codman’s Triangle:** Classic radiological signs of Osteosarcoma. * **Ground Glass Appearance:** Fibrous Dysplasia.

Q: Peak incidence of osteosarcoma occurs at which decade of life?

2nd decade. **Explanation:** **Osteosarcoma** is the most common primary malignant bone tumor in children and adolescents. The peak incidence occurs in the **2nd decade of life (10–20 years)**. **Why the 2nd decade is correct:** This peak coincides with the **adolescent growth spurt**. Osteosarcoma typically arises in the metaphyseal region of long bones (most commonly the distal femur, followed by the proximal tibia and proximal humerus), where there is maximum osteoblastic activity and rapid bone turnover. The high rate of cell division during this period increases the likelihood of oncogenic mutations. **Analysis of Incorrect Options:** * **3rd decade:** While cases occur, the incidence drops significantly after skeletal maturity is reached. * **5th and 6th decades:** These represent the **secondary peak** of osteosarcoma. When osteosarcoma occurs in older adults, it is usually not "primary" but secondary to pre-existing conditions such as **Paget’s disease of bone**, post-radiation therapy, or bone infarcts. **High-Yield Clinical Pearls for NEET-PG:** * **Radiology:** Characteristic features include the **Sunray/Sunburst appearance** (due to spiculated periosteal reaction) and **Codman’s triangle** (elevation of the periosteum). * **Site:** Most common site is the **distal femur** (around the knee). * **Metastasis:** It spreads primarily via the hematogenous route, most commonly to the **lungs** (skip lesions may also be present in the same bone). * **Biomarker:** Serum **Alkaline Phosphatase (ALP)** levels are often elevated and serve as a marker for prognosis and treatment response. * **Treatment:** The standard of care is **Neoadjuvant chemotherapy** followed by limb-salvage surgery and postoperative chemotherapy.

Q: Which bone tumor is characterized by patchy calcification on X-ray?

Chondroblastoma. ### Explanation **Correct Answer: B. Chondroblastoma** **Why it is correct:** Chondroblastoma is a rare, benign cartilaginous tumor that characteristically arises in the **epiphysis** of long bones (most commonly the proximal humerus, distal femur, and proximal tibia) in skeletally immature patients. On X-ray, it appears as a well-defined lytic lesion with a thin sclerotic rim. The hallmark radiological feature is **patchy, "fluffy," or "popcorn" calcification** within the lytic area. This occurs due to the focal calcification of the chondroid matrix, often described histologically as **"Chicken-wire calcification."** **Why the other options are incorrect:** * **A. Osteosarcoma:** Typically presents with a **"Sunburst appearance"** or **"Codman’s triangle"** due to aggressive periosteal reaction. While it produces osteoid (bone), the pattern is usually dense and cloud-like rather than discrete patchy calcification. * **C. Fibrous Dysplasia:** Characterized by a **"Ground-glass appearance"** on X-ray. This is due to the replacement of normal bone with fibrous tissue and haphazardly arranged bony trabeculae, resulting in a hazy, smoky opacity. * **D. Osteoclastoma (Giant Cell Tumor):** Also occurs in the epiphysis (after growth plate closure), but it is classically described as a **"Soap-bubble appearance."** It is a purely lytic lesion and typically lacks internal calcification. **NEET-PG High-Yield Pearls:** * **Location:** Chondroblastoma is one of the few tumors found in the **Epiphysis** (Mnemonic: **C**hondroblastoma, **G**iant Cell Tumor, **E**piphyseal—"**CGE**"). * **Age:** Usually occurs in the 2nd decade (10–20 years), before the epiphyseal plate closes. * **Histology:** Look for **"Chicken-wire calcification"** (calcification surrounding individual chondroblasts). * **Treatment:** Curettage and bone grafting.

Q: What is the LEAST common cause of a proximal lytic lesion of the head of the femur in a 13-year-old boy?

Plasmacytoma. **Explanation** The correct answer is **Plasmacytoma**. The primary factor in solving this question is the **age of the patient (13 years old)**. **1. Why Plasmacytoma is the correct answer:** Plasmacytoma (a localized plasma cell neoplasm) and Multiple Myeloma are diseases of the elderly, typically occurring in patients over **50–60 years of age**. It is virtually unheard of in the pediatric or early adolescent population. Therefore, in a 13-year-old, it is the least likely cause of a lytic lesion. **2. Analysis of Incorrect Options:** * **Metastasis:** While more common in adults, certain pediatric tumors like **Neuroblastoma** or **Rhabdomyosarcoma** can frequently metastasize to the proximal femur in children. * **Histiocytosis:** Specifically **Langerhans Cell Histiocytosis (LCH)**, is a classic cause of "punched-out" lytic lesions in children and adolescents. The femur is a common site for eosinophilic granuloma (a form of LCH). * **Bone Tumour:** Several primary bone tumors occur in this age group. A lytic lesion in the femoral head/neck of a 13-year-old is highly suspicious for a **Chondroblastoma** (which characteristically involves the epiphysis) or a **Simple Bone Cyst**. **Clinical Pearls for NEET-PG:** * **Epiphyseal Lytic Lesions (Mnemonic: "C-G-I"):** **C**hondroblastoma (children), **G**iant Cell Tumor (adults/closed epiphysis), **I**nfection (Brodie’s Abscess). * **Multiple Myeloma/Plasmacytoma:** Always suspect in lytic lesions in patients **>40 years**. It is the most common primary bone malignancy in adults. * **Langerhans Cell Histiocytosis:** Often presents as a "vertebra plana" in the spine or a "beveled edge" lesion in the skull of a child.

Q: Diaphyseal aclasis is defined as which of the following?

Multiple exostosis. **Explanation:** **Diaphyseal aclasis**, also known as **Hereditary Multiple Exostoses (HME)**, is an autosomal dominant condition characterized by the development of multiple osteochondromas (exostoses) at the metaphyseal ends of long bones. The term "aclasis" refers to the failure of normal bone modeling, leading to a characteristic broadening of the metaphysis as the tumor grows. * **Why Option A is correct:** Diaphyseal aclasis is the synonymous clinical term for multiple exostoses. These are benign, cartilage-capped bony outgrowths. They typically present in the first decade of life and can lead to skeletal deformities, such as Madelung-like deformity or limb length discrepancy. * **Why Option B is incorrect:** Multiple enchondromatosis is known as **Ollier’s disease**. If associated with hemangiomas, it is called **Maffucci syndrome**. Enchondromas are intramedullary cartilage tumors, unlike the surface-based exostoses. * **Why Option C is incorrect:** Multiple hemangiomas are seen in conditions like Maffucci syndrome or Gorham-Stout disease (disappearing bone disease), but they are not referred to as diaphyseal aclasis. * **Why Option D is incorrect:** Osteoid osteoma is a benign osteoblastic tumor characterized by a radiolucent nidus. It is typically solitary; multiple occurrences are extremely rare and do not constitute diaphyseal aclasis. **High-Yield Clinical Pearls for NEET-PG:** * **Genetics:** Associated with mutations in **EXT1** (Chromosome 8) and **EXT2** (Chromosome 11) genes. * **Malignant Transformation:** There is a **1-5% risk** of transformation into secondary **Chondrosarcoma**. A sudden increase in size or a cartilage cap thickness **>2 cm** in adults suggests malignancy. * **Radiology:** The cortex and medullary cavity of the exostosis are continuous with the host bone.

Q: Which bone tumor is hormone-dependent?

Fibrous dysplasia. ### Explanation **Correct Answer: D. Fibrous dysplasia** **Why it is correct:** Fibrous dysplasia is a condition where normal bone is replaced by fibrous connective tissue and disorganized bony trabeculae. It is considered **hormone-dependent** because the lesional cells (osteoblasts) express increased levels of **estrogen receptors**. Clinical progression or enlargement of the lesion is frequently observed during periods of high hormonal activity, such as **pregnancy** or puberty. Furthermore, fibrous dysplasia is a hallmark component of **McCune-Albright Syndrome**, which is characterized by the triad of polyostotic fibrous dysplasia, café-au-lait spots, and hyperfunctioning endocrinopathies (like precocious puberty). **Why the other options are incorrect:** * **A. Osteogenic sarcoma:** This is a primary malignant bone tumor characterized by the production of osteoid. While it has a bimodal age distribution (linked to growth spurts), it is not considered a hormone-dependent tumor. * **B. Ewing sarcoma:** This is a small round blue cell tumor associated with the t(11;22) translocation. Its pathogenesis is genetic/molecular rather than hormonal. * **C. Osteoclastoma (Giant Cell Tumor):** While GCT is common in females of reproductive age and may expand during pregnancy due to increased vascularity, it is not classified as a hormone-dependent tumor in the same pathophysiological context as fibrous dysplasia. **High-Yield NEET-PG Pearls:** * **Radiology:** Characterized by a classic **"Ground Glass Appearance"** on X-ray. * **Histology:** Shows irregular bony trabeculae without osteoblastic rimming, often described as **"Chinese Letter Pattern."** * **McCune-Albright Syndrome:** Caused by a somatic mutation in the **GNAS1 gene**, leading to constitutive activation of adenylate cyclase. * **Monostotic vs. Polyostotic:** Monostotic (70%) is the most common form; the femur is the most common site.

Q: Which among the following bone tumors is radioresistant?

All the above. **Explanation:** The sensitivity of a tumor to radiation depends on its cellular kinetics and origin. In orthopaedics, bone tumors are broadly classified into **radiosensitive** (e.g., Ewing’s sarcoma, Multiple Myeloma, Lymphoma) and **radioresistant** (e.g., Osteosarcoma, Chondrosarcoma). **Why "All the above" is correct:** * **Osteosarcoma (Option A):** This is a primary malignant bone tumor characterized by the production of osteoid. It is notoriously radioresistant; therefore, radiotherapy is rarely used as a primary treatment, with surgery and chemotherapy being the mainstays. * **Fibrosarcoma (Option B):** This spindle-cell tumor of the bone or soft tissue also shows a poor response to radiation. Surgical excision with wide margins is the preferred treatment. * **Melanoma (Option C):** Although primarily a skin malignancy, melanoma can metastasize to the bone. It is classically described as radioresistant due to efficient DNA repair mechanisms and high levels of antioxidants within the cells. **Clinical Pearls for NEET-PG:** 1. **Most Radiosensitive Bone Tumor:** Ewing’s Sarcoma (often treated with the VAC regimen + Radiotherapy). 2. **Highly Radioresistant:** Chondrosarcoma is another high-yield example of a radioresistant bone tumor. 3. **Palliative Exception:** Even in radioresistant tumors like Osteosarcoma, radiotherapy may be used for **palliative purposes** (to reduce pain in advanced stages) but not for curative intent. 4. **Mnemonic for Radiosensitive Tumors:** "E-M-L" (Ewing’s, Myeloma, Lymphoma).

Q: What is the most common cause of bone malignancy?

Metastatic disease (secondaries). **Explanation:** The most common cause of bone malignancy overall is **Metastatic disease (secondaries)**. In clinical practice, secondary deposits from primary carcinomas (most commonly breast, prostate, lung, and kidney) far outnumber primary bone tumors. While primary bone tumors are rare, bone is the third most common site for metastatic spread after the lung and liver. **Analysis of Options:** * **A. Metastatic disease (Correct):** Statistically, metastatic involvement of the skeleton is significantly more frequent than primary bone cancers, especially in patients over the age of 40. * **B. Osteosarcoma:** This is the most common **primary** malignant bone tumor (excluding multiple myeloma). It typically affects the adolescent age group and occurs at the metaphysis of long bones. * **C. Ewing's sarcoma:** This is the second most common primary malignant bone tumor in children and young adults. It is characterized by small round blue cells and an "onion skin" periosteal reaction. * **D. Osteoclastoma (Giant Cell Tumor):** This is a "locally aggressive" tumor rather than a purely malignant one. While it can metastasize (rarely to the lungs), it is primarily classified as a benign but destructive lesion. **High-Yield Clinical Pearls for NEET-PG:** * **Most common primary bone malignancy:** Multiple Myeloma (if included in options); if not, Osteosarcoma. * **Most common site for bone metastasis:** Spine (Vertebral column). * **Osteoblastic (Sclerotic) Metastasis:** Classically seen in Carcinoma Prostate. * **Osteolytic Metastasis:** Classically seen in Carcinoma Kidney, Thyroid, and Lung. * **Mixed Metastasis:** Classically seen in Carcinoma Breast.

Q: Which of the following is associated with poor prognosis in Ewing's sarcoma?

Fever. **Explanation:** Ewing’s Sarcoma is a highly malignant small round blue cell tumor. Prognosis is determined by several clinical and laboratory parameters. **Why Fever is the Correct Answer:** Systemic symptoms, specifically **fever**, weight loss, and anemia at the time of presentation, are well-established indicators of a **high tumor burden** and potentially metastatic disease. In Ewing’s sarcoma, fever is often associated with a larger primary tumor volume (>100 ml) and an elevated Erythrocyte Sedimentation Rate (ESR), both of which correlate with a significantly poorer prognosis and decreased disease-free survival. **Analysis of Incorrect Options:** * **Beta-2 microglobulin:** This is a prognostic marker primarily used in hematological malignancies like **Multiple Myeloma** and lymphomas, not Ewing’s sarcoma. * **Thrombocytosis:** While an elevated white blood cell count or ESR can be seen, thrombocytosis is not a standard prognostic marker for Ewing’s. However, **LDH (Lactate Dehydrogenase)** levels are a significant prognostic indicator (high LDH = poor prognosis). * **Young age:** In Ewing’s sarcoma, **older age** (typically >15 years) is actually associated with a poorer prognosis. Younger children generally have better outcomes. **NEET-PG High-Yield Pearls:** * **Most important prognostic factor:** Presence of metastasis at presentation (most commonly to lungs). * **Anatomical site:** Pelvic tumors have a worse prognosis than distal extremity tumors. * **Genetics:** Characterized by **t(11;22)** translocation involving the *EWS-FLI1* gene. * **Radiology:** Classic "Onion-skin" periosteal reaction. * **Histology:** PAS positive (due to glycogen) and CD99 (MIC2) positive.

Q: All the statements are true about exostosis except?

Growth continues after skeletal maturity. **Exostosis**, also known as **Osteochondroma**, is the most common benign bone tumor. It is a developmental anomaly rather than a true neoplasm, characterized by a cartilage-capped bony outgrowth on the surface of the bone. ### **Explanation of Options** * **Correct Answer (B): Growth continues after skeletal maturity.** The growth of an osteochondroma is strictly linked to the activity of the epiphyseal growth plate. Therefore, **growth typically ceases once the person reaches skeletal maturity** (when the growth plates close). If an exostosis starts growing again in an adult, it is a major "red flag" for malignant transformation into a Chondrosarcoma. * **Option A: It occurs at the growing end of bone.** This is true. Exostosis typically arises from the **metaphysis** of long bones (most commonly the distal femur and proximal tibia) near the growth plate. * **Option C: It is covered by a cartilaginous cap.** This is true. The tumor is composed of a bony stalk (pedunculated or sessile) that is continuous with the host bone's cortex and medullary cavity, topped by a **hyaline cartilage cap**. * **Option D: Malignant transformation may occur.** This is true. While rare ( 2 cm** in an adult is highly suggestive of malignancy. 3. **Genetics:** Associated with mutations in **EXT1 and EXT2** genes. 4. **Treatment:** Asymptomatic lesions are managed conservatively. Surgical excision is indicated only if the lesion is painful, interferes with joint movement, or shows signs of malignancy.

Question 1

Which of the following tumors is the most chemoresistant?

Accepted Answer

Malignant fibrous histiocytoma

Answer

Synovial sarcoma

Answer

Osteosarcoma

Answer

Embryonal rhabdomyosarcoma

Question 2

Peak incidence of osteosarcoma occurs at which decade of life?

Accepted Answer

2nd decade

Answer

3rd decade

Answer

5th decade

Answer

6th decade

Question 3

Which bone tumor is characterized by patchy calcification on X-ray?

Accepted Answer

Chondroblastoma

Answer

Osteosarcoma

Answer

Fibrous dysplasia

Answer

Osteoclastoma

Question 4

What is the LEAST common cause of a proximal lytic lesion of the head of the femur in a 13-year-old boy?

Accepted Answer

Plasmacytoma

Answer

Metastasis

Answer

Histiocytosis

Answer

Bone tumour

Question 5

Diaphyseal aclasis is defined as which of the following?

Accepted Answer

Multiple exostosis

Answer

Multiple enchondromatosis

Answer

Multiple hemangioma

Answer

Multiple osteoid osteoma

Question 6

Which bone tumor is hormone-dependent?

Accepted Answer

Fibrous dysplasia

Answer

Osteogenic sarcoma

Answer

Ewing sarcoma

Answer

Osteoclastoma

Question 7

Which among the following bone tumors is radioresistant?

Accepted Answer

All the above

Answer

Osteosarcoma

Answer

Fibrosarcoma

Answer

Melanoma

Question 8

What is the most common cause of bone malignancy?

Accepted Answer

Metastatic disease (secondaries)

Answer

Osteosarcoma

Answer

Ewing's sarcoma

Answer

Osteoclastoma

Question 9

Which of the following is associated with poor prognosis in Ewing's sarcoma?

Accepted Answer

Fever

Answer

Beta-2 microglobulin

Answer

Thrombocytosis

Answer

Young age

Question 10

All the statements are true about exostosis except?

Accepted Answer

Growth continues after skeletal maturity

Answer

It occurs at the growing end of bone

Answer

It is covered by a cartilaginous cap

Answer

Malignant transformation may occur

Bone Tumors — MCQs

Bone Tumors — MCQs

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