Malignant Primary Bone Tumors Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Malignant Primary Bone Tumors. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Malignant Primary Bone Tumors Indian Medical PG Question 1: What is the most common structural location within the bone for conventional chondrosarcoma?
- A. Intramedullary (Correct Answer)
- B. Juxtacortical
- C. Epiphyseal
- D. Periosteal
Malignant Primary Bone Tumors Explanation: ***Intramedullary***
- This is the **most common location** for conventional chondrosarcoma, accounting for approximately **75-85%** of cases [1].
- These tumors arise within the **medullary cavity** (central or intramedullary location) and grow expansively within the bone [1].
- They typically show lytic destruction with internal ring-and-arc or popcorn calcifications on imaging.
- Conventional chondrosarcoma is synonymous with central or intramedullary chondrosarcoma [1].
*Periosteal*
- Periosteal (surface) chondrosarcoma is a **rare subtype** accounting for only **1-2%** of chondrosarcomas.
- These arise from the periosteum on the bone surface, not within the medullary cavity.
- They have a better prognosis compared to conventional (intramedullary) chondrosarcoma.
*Juxtacortical*
- This refers to tumors arising at or near the **bone surface** (cortical region) [1].
- Peripheral/juxtacortical chondrosarcoma accounts for approximately **10-15%** of cases and is much less common than the central type.
- Secondary chondrosarcoma arising from osteochondroma is an example of peripheral chondrosarcoma [1].
*Epiphyseal*
- Chondrosarcoma **rarely arises in the epiphysis** of long bones.
- Conventional chondrosarcoma typically involves the **metaphysis and diaphysis**, with predilection for flat bones (pelvis, ribs) and long bones (femur, humerus) [2].
- Epiphyseal location would be highly unusual for this tumor.
**References:**
[1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1202-1204.
[2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 673-674.
Malignant Primary Bone Tumors Indian Medical PG Question 2: Popcorn calcification is seen in
- A. Adamantinoma
- B. Chondrosarcoma (Correct Answer)
- C. Osteosarcoma
- D. Multiple myeloma
Malignant Primary Bone Tumors Explanation: ***Chondrosarcoma***
- **Popcorn calcification** is a classic radiographic sign frequently observed in **chondrosarcoma**, representing calcified cartilage matrix.
- This type of calcification is typically seen in tumors arising from **cartilaginous tissue**.
*Adamantinoma*
- Adamantinoma is a rare, malignant bone tumor characterized by **epithelial cell nests** within a fibrous stroma, primarily affecting the **tibia**.
- It usually presents with **lytic lesions** and often contains areas of calcification, but not typically the "popcorn" pattern.
*Osteosarcoma*
- Osteosarcoma is characterized by the production of **osteoid** by malignant osteoblasts.
- Radiographically, it often shows a **sunburst pattern** or **Codman's triangle**, indicative of aggressive periosteal reaction and calcified tumor matrix, distinct from popcorn calcification.
*Multiple myeloma*
- Multiple myeloma is a **hematologic malignancy** involving plasma cells, leading to widespread osteolytic lesions.
- It typically presents as **punched-out lytic lesions** without calcification or osteoblastic activity.
Malignant Primary Bone Tumors Indian Medical PG Question 3: Which of the following conditions is not typically associated with an underlying malignancy?
- A. Paget disease of vulva
- B. Paget disease of anal region
- C. Paget disease of bone (Correct Answer)
- D. Paget disease of nipple
Malignant Primary Bone Tumors Explanation: ***Paget disease of bone***
- While Paget disease of bone can rarely undergo **malignant transformation** into **osteosarcoma**, it is itself a disorder of excessive bone remodeling and **not directly an underlying malignancy** like the other Paget diseases [2].
- The primary concern in Paget disease of bone is metabolic bone changes and potential complications like fractures, rather than being a superficial manifestation of internal cancer [2].
*Paget disease of nipple*
- This condition is almost always associated with an **underlying ductal carcinoma in situ** or invasive adenocarcinoma of the breast [1].
- The epidermal changes are a manifestation of malignant cells migrating from the underlying breast tissue [1].
*Paget disease of vulva*
- While it can occur as a primary intraepithelial neoplasm (adenocarcinoma in situ), approximately 20-30% of cases are associated with an **underlying invasive adenocarcinoma**, either vulvar or originating from other sites such as the colon, bladder, or urethra.
- Its presence necessitates a thorough search for associated malignancies.
*Paget disease of anal region*
- Similar to vulvar Paget disease, it can be a primary intraepithelial adenocarcinoma, but it frequently is associated with an **underlying adenocarcinoma** of the colon, rectum, or anal glands.
- Evaluation for an internal malignancy is crucial when this diagnosis is made.
**References:**
[1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Breast, pp. 1061-1062.
[2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1191-1194.
Malignant Primary Bone Tumors Indian Medical PG Question 4: "Sunray appearance" on X-rays is suggestive of:
- A. A metastatic tumour in the bone
- B. An Osteogenic sarcoma (Correct Answer)
- C. An Ewing's sarcoma
- D. A type of bone cancer that can show various radiographic appearances
Malignant Primary Bone Tumors Explanation: ***An Osteogenic sarcoma***
- The **"sunray appearance" (or sunburst)** on X-rays is a classic radiographic finding pathognomonic for **osteosarcoma**, especially in adults and adolescents.
- This appearance is due to the **periosteal new bone formation** that grows perpendicular to the bone surface, creating a radiating spicule pattern.
*A type of bone cancer that can show various radiographic appearances*
- While true that bone cancers can show various appearances, the "sunray appearance" is specific enough to strongly point to a particular type, rather than just a general category.
- This option is too broad and does not provide the most precise diagnosis indicated by the specific radiographic sign.
*A metastatic tumour in the bone*
- Metastatic bone lesions typically present with **lytic (bone destruction)** or **blastic (bone formation)** patterns, or a mixed pattern, but rarely produce the periosteal "sunray" appearance.
- The characteristic radiographic finding for metastasis would often involve multiple lesions and different periosteal reactions, such as an **onion skin appearance** in some aggressive cases, but not typically sunray.
*An Ewing's sarcoma*
- Ewing's sarcoma commonly presents with an **"onion skin" periosteal reaction** due to multiple layers of new bone formation.
- While both are primary bone tumors, the radiographic findings are distinctly different, allowing for differentiation.
Malignant Primary Bone Tumors Indian Medical PG Question 5: A 13-year-old boy, previously healthy, presents with a 1-month history of right leg pain, without trauma or recent illness. Physical examination reveals warmth, tenderness, and increased circumference of the right thigh compared to the left. His temperature is 39°C. A radiograph shows a 6-cm expansile mass in the diaphyseal region of the right lower femur, extending into soft tissue and covered by reactive bone. Microscopic examination of the mass biopsy reveals sheets of primitive cells with small, uniform nuclei and scant cytoplasm. Karyotypic analysis shows a t(11;22) translocation. What is the most likely diagnosis?
- A. Ewing sarcoma (Correct Answer)
- B. Chondrosarcoma
- C. Giant cell tumor
- D. Metastatic carcinoma
Malignant Primary Bone Tumors Explanation: ***Ewing sarcoma***
- The patient's age (13-year-old), symptoms (bone pain, systemic fever), **diaphyseal location** of the tumor, and especially the characteristic histological finding of **small, uniform cells** (small round blue cell tumor) with **scant cytoplasm** point towards Ewing sarcoma.
- The presence of **t(11;22)(q24;q12) translocation** resulting in the **EWSR1-FLI1 fusion gene** is a definitive diagnostic marker for Ewing sarcoma (present in ~85% of cases), distinguishing it from other bone tumors.
*Chondrosarcoma*
- This tumor typically affects older adults (>40 years) and arises from cartilage, showing cartilaginous matrix on histology.
- It lacks the specific t(11;22) translocation seen in this patient.
*Giant cell tumor*
- Giant cell tumors typically occur in young adults (20-40 years) and are usually found in the **epiphyseal and metaphyseal regions** of long bones.
- Histologically, they contain numerous **multinucleated giant cells** interspersed with mononuclear stromal cells, not sheets of primitive cells.
*Metastatic carcinoma*
- Metastatic carcinoma to bone is rare in children and usually occurs in older adults with a known primary cancer.
- The histology of "sheets of primitive cells with small, uniform nuclei and scant cytoplasm" is not typical for metastatic carcinoma.
Malignant Primary Bone Tumors Indian Medical PG Question 6: A 45 yrs male presented with an expansile lesion in the centre of femoral metaphysis. The lesion shows Endosteal scalloping and punctuate calcifications. Most likely diagnosis is:
- A. Fibrous Dysplasia
- B. Chondrosarcoma (Correct Answer)
- C. Simple bone cyst
- D. Osteosarcoma
Malignant Primary Bone Tumors Explanation: ***Chondrosarcoma***
- An **expansile lesion** within the **femoral metaphysis** with **endosteal scalloping** and **punctate calcifications** is highly characteristic of a chondrosarcoma.
- The punctate/arc-and-ring calcifications are typical for cartilage matrix, which is the hallmark of chondrosarcoma, and the patient's age (45 years) fits the typical demographic.
*Fibrous Dysplasia*
- This condition presents as a **ground-glass matrix** on imaging, not punctate calcifications.
- While it can be expansile, it typically does not show prominent endosteal scalloping with cartilage calcifications.
*Simple bone cyst*
- Simple bone cysts are typically **lytic lesions** that do not show punctate calcifications or aggressive endosteal scalloping.
- They are often **fluid-filled** and common in children/adolescents, whereas this patient is 45 years old.
*Osteosarcoma*
- Osteosarcomas are characterized by **osteoid matrix formation** and often have a more aggressive appearance with a **sunburst or spiculated periosteal reaction** and bone formation, not punctate cartilage calcifications.
- While it can be expansile, the calcification pattern described points away from osteosarcoma.
Malignant Primary Bone Tumors Indian Medical PG Question 7: An 8 yr old child is having fever with pain and swelling in mid thigh. On Xray lamellated appearance and Codman's triangle is present. Histopathologic examination shows small round cells positive for MIC-2. What is the most likely diagnosis?
- A. Chondrosarcoma
- B. Chondroblastoma
- C. Ewings sarcoma (Correct Answer)
- D. Osteosarcoma
Malignant Primary Bone Tumors Explanation: ***Ewings sarcoma***
- The combination of **fever with pain and swelling** in a child, **lamellated (onion-skin) periosteal reaction**, **Codman's triangle** on X-ray, and **small round cells positive for MIC-2 (CD99)** on histopathology is classic for Ewing's sarcoma.
- This highly aggressive bone tumor primarily affects children and young adults, often presenting with systemic symptoms and a diaphyseal or metadiaphyseal location in long bones.
*Chondrosarcoma*
- This tumor is characterized by the production of **cartilage matrix** and typically affects older adults (40-70 years old), not children.
- Radiographically, it often shows **calcifications with rings and arcs** within a lucent lesion, and histopathology reveals chondrocytes, not small round cells positive for MIC-2.
*Chondroblastoma*
- Chondroblastoma is a rare, **benign cartilage tumor** that typically occurs in the **epiphysis of long bones** in adolescents and young adults.
- It usually presents as a well-defined lytic lesion and does not typically show lamellated periosteal reactions or positive MIC-2 staining, nor does it commonly present with fever.
*Osteosarcoma*
- While osteosarcoma is also an aggressive bone tumor affecting children and adolescents, it is characterized by the production of **osteoid (immature bone)**.
- Radiographically, it often presents with a **"sunburst" pattern** due to spiculated periosteal reaction and a **Codman's triangle**, but histopathology shows malignant osteoblasts, not small round cells positive for MIC-2.
Malignant Primary Bone Tumors Indian Medical PG Question 8: Which of the following is a bone-forming malignant tumor?
- A. Osteoid osteoma
- B. Osteosarcoma (Correct Answer)
- C. Chondroblastoma
- D. Giant cell tumor
Malignant Primary Bone Tumors Explanation: ***Osteosarcoma***
- **Osteosarcoma** is the most common **primary malignant bone tumor**, characterized by the production of **osteoid** (immature bone) by malignant osteoblasts [1], [2].
- It typically arises in the **metaphysis of long bones** (e.g., distal femur, proximal tibia, proximal humerus) and often presents with pain and swelling [1], [2].
*Osteoid osteoma*
- **Osteoid osteoma** is a benign bone tumor characterized by a small nidus of **osteoid-forming tissue** surrounded by sclerotic bone.
- While it involves osteoid formation, it is **not malignant** and does not metastasize.
*Chondroblastoma*
- **Chondroblastoma** is a rare, **benign cartilage-forming tumor** that typically occurs in the **epiphysis of long bones** in skeletally immature individuals.
- It is composed of chondroblast-like cells and does not produce osteoid or show malignant features.
*Giant cell tumor*
- **Giant cell tumor** of bone is an **aggressive, locally destructive benign tumor** characterized by numerous osteoclast-like giant cells and spindle-shaped stromal cells.
- It arises in the **epiphysis/metaphysis** of long bones (e.g., distal femur, proximal tibia) but is not a bone-forming tumor and is typically not malignant, though it has a high recurrence rate.
**References:**
[1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 671-674.
[2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1200-1202.
Malignant Primary Bone Tumors Indian Medical PG Question 9: The image shows a wrist deformity and an X-ray of a bone lesion near the distal radius. Based on the clinical and radiological features, what is the most likely diagnosis?
- A. Ewings Sarcoma
- B. Osteochondroma
- C. Giant Cell Tumor (GCT) (Correct Answer)
- D. Osteoid Osteoma
Malignant Primary Bone Tumors Explanation: ***Giant Cell Tumor (GCT)***
* The image shows a **lytic (lucid) lesion** located in the **epiphysis/metaphysis of the distal radius**, which is a classic presentation site for GCT.
* GCTs are typically seen in individuals aged 20-40, often present with **pain, swelling, and reduced range of motion**, and can show a **soap bubble appearance** on X-ray even with cortical erosion as seen in the image.
*Ewing's Sarcoma*
* Ewing's Sarcoma commonly affects the **diaphysis of long bones** and may present with an **onion skin periosteal reaction**, none of which are clearly depicted.
* It primarily affects children and young adults (5-20 years old), which does not align with the assumed adult presentation given the fused epiphysis.
*Osteochondroma*
* Osteochondromas are **bony prominences covered by cartilage** and grow **outward from the bone surface**, often away from the joint, unlike the intraosseous lytic lesion seen.
* They typically appear as **pedunculated or sessile exostoses** and are benign growth plate abnormalities, not lytic lesions of the marrow cavity.
*Osteoid Osteoma*
* Osteoid osteomas are characterized by a **small lucent nidus** (usually <1.5 cm) surrounded by a significant margin of **sclerotic bone**, which is not seen here.
* They classically cause **nocturnal pain** relieved by NSAIDs and are typically smaller than the lesion depicted, which appears expansile.
Malignant Primary Bone Tumors Indian Medical PG Question 10: Most common site of adamantinoma of the long bones is -
- A. Tibia (Correct Answer)
- B. Ulna
- C. Fibula
- D. Femur
Malignant Primary Bone Tumors Explanation: ***Tibia***
- Adamantinoma is a rare, malignant bone tumor that has a strong predilection for the **tibia**, accounting for approximately 85-90% of cases in long bones.
- It most commonly occurs in the **diaphysis of the tibia** but can also be found in the metaphysis.
*Ulna*
- While adamantinoma can rarely affect other long bones, the **ulna is not a common site** for its occurrence.
- The incidence of adamantinoma in the upper extremities, including the ulna, is significantly lower compared to the tibia.
*Fibula*
- The **fibula is an uncommon site** for adamantinoma, with only a small percentage of cases reported in this bone.
- When it does occur in the fibula, it usually involves the mid-diaphysis.
*Femur*
- The **femur is also a rare location** for adamantinoma, with only a handful of cases documented in medical literature.
- The vast majority of adamantinomas consistently originate in the lower leg, particularly the tibia.
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