Bone Tumors Practice Questions

Q: Which of the following is NOT TRUE about aneurysmal bone cyst?

Diagnosis is by FNAC. ### Explanation: Aneurysmal Bone Cyst (ABC) **Why Option C is NOT TRUE:** The diagnosis of an Aneurysmal Bone Cyst (ABC) cannot be reliably made by **Fine Needle Aspiration Cytology (FNAC)**. Because ABCs are composed of large, blood-filled spaces, FNAC typically yields only frank blood, which is non-diagnostic. The gold standard for diagnosis is a **core needle biopsy or open biopsy**, which reveals characteristic fibrous septa containing spindle cells, multinucleated giant cells, and osteoid, without an endothelial lining. **Analysis of Other Options:** * **Option A (Expansile, blood-filled cyst):** This is a classic description. ABC is a benign but locally aggressive lesion characterized by reactive vascular proliferation that creates "blow-out" expansion of the bone. * **Option B (Most common in the upper end of tibia):** ABCs most commonly affect the metaphysis of long bones. The **distal femur and proximal tibia** (around the knee) are the most frequent sites, followed by the vertebrae (posterior elements). * **Option D (Is a pseudocyst):** ABC is considered a **pseudocyst** because its blood-filled cavities are lined by fibroblasts and histiocytes rather than a true epithelial or endothelial lining. **NEET-PG High-Yield Pearls:** * **Radiology:** Shows a "Soap Bubble" appearance (eccentric, expansile, lytic lesion). * **MRI Finding:** **Fluid-fluid levels** are a hallmark (due to sedimentation of RBCs), though not pathognomonic as they can also be seen in Giant Cell Tumors (GCT). * **Genetics:** Associated with **USP6 gene** rearrangement on chromosome 17p13. * **Treatment:** Curettage and bone grafting. Liquid nitrogen or phenol are often used as adjuvants to reduce recurrence.

Q: An 8-year-old child presented with pain at the shoulder and arm. An X-ray reveals a uniform, well-defined lucent lesion at the metaphysis. What is the most likely diagnosis?

Simple bone cyst. **Explanation:** The clinical presentation and radiographic findings are classic for a **Simple Bone Cyst (SBC)**, also known as a Unicameral Bone Cyst. **Why Simple Bone Cyst is correct:** SBCs are benign, fluid-filled cavities typically found in children (5–15 years). They characteristically occur in the **metaphysis** of long bones, most commonly the **proximal humerus** (shoulder) and proximal femur. On X-ray, they appear as **centrally located, well-defined, symmetric lucent lesions** with a "thinning" of the cortex. A pathognomonic sign often seen after a pathological fracture is the "Fallen Leaf Sign." **Why other options are incorrect:** * **Aneurysmal Bone Cyst (ABC):** While also occurring in the metaphysis of young patients, ABCs are typically **eccentric** (off-center) and "expansile," giving a "soap-bubble" appearance. They are often more painful and aggressive than SBCs. * **Giant Cell Tumor (GCT):** GCTs are **epiphyseal** lesions that occur after skeletal maturity (20–40 years). They are eccentric and reach the subchondral bone, which does not fit the age or location (metaphysis) in this case. * **Osteoid Osteoma:** This presents with severe nocturnal pain relieved by NSAIDs. Radiographically, it shows a small radiolucent **nidus** ( Proximal Femur. * **Fallen Leaf Sign:** Pathognomonic for SBC (a cortical fragment settles at the bottom of the fluid-filled cyst). * **Management:** Observation or aspiration/steroid injection; surgery is reserved for large cysts at risk of fracture. * **SBC vs. ABC:** SBC is **central** and latent; ABC is **eccentric** and expansile.

Q: A 8-year-old male child presented with complaints of pain and swelling in the right distal femur for 5 months, along with intermittent fever, significant weight loss, and loss of appetite. Lab studies revealed anemia, leukocytosis, and elevated ESR & LDH. There was no history of trauma. Which of the following chromosomal abnormalities is characteristic of this lesion?

t(11:22). ### Explanation **Diagnosis: Ewing Sarcoma** The clinical presentation of a young child (8 years old) with pain, swelling in the distal femur, and systemic symptoms (fever, weight loss, anemia, elevated ESR/LDH) is classic for **Ewing Sarcoma**. This tumor often mimics osteomyelitis clinically but is characterized radiologically by an "onion-skin" periosteal reaction and histologically by small round blue cells. **1. Why Option B is Correct:** Ewing Sarcoma is defined by specific reciprocal chromosomal translocations. In approximately 85–90% of cases, the translocation is **t(11;22)(q24;q12)**. This results in the fusion of the **EWS gene** on chromosome 22 to the **FLI1 gene** on chromosome 11, creating a chimeric transcription factor that drives oncogenesis. **2. Analysis of Incorrect Options:** * **Option A: t(15;17):** Characteristic of **Acute Promyelocytic Leukemia (APML)** (M3 subtype of AML), involving the PML-RARA fusion. * **Option C: t(6;6):** Not a standard high-yield translocation for major bone tumors or hematological malignancies. * **Option D: t(8;21):** Characteristic of **Acute Myeloid Leukemia (AML-M2)**. **3. Clinical Pearls for NEET-PG:** * **Age Group:** Most common in the 5–15 year age group (second most common primary bone tumor in children after Osteosarcoma). * **Location:** Diaphysis of long bones (Femur is the most common site). * **Radiology:** "Onion-skin" appearance (layers of new bone) and "Sunray" or "Hair-on-end" appearance (though less common than in Osteosarcoma). * **Histology:** Small round blue cells; **PAS positive** (due to cytoplasmic glycogen); **CD99 (MIC2)** is a highly sensitive marker. * **Prognosis:** Serum LDH levels are a useful marker for tumor burden and prognosis.

Q: Chemotherapy of Ewing's sarcoma includes all except?

5-Fluorouracil. **Explanation:** Ewing’s Sarcoma is a highly malignant, small round blue cell tumor that is exquisitely sensitive to chemotherapy. The standard of care involves a multimodal approach (Chemotherapy + Surgery/Radiotherapy). **Why 5-Fluorouracil (5-FU) is the correct answer:** 5-Fluorouracil is an antimetabolite primarily used in the treatment of epithelial malignancies (GI tract, breast, and head/neck cancers). It has **no established role** in the management of Ewing’s Sarcoma. **Analysis of other options (The VAC-IE Regimen):** The current standard chemotherapy for Ewing's Sarcoma follows the **VAC-IE** protocol, which includes: * **Vincristine** * **Actinomycin D (Dactinomycin):** An antitumor antibiotic that inhibits RNA synthesis (Option B). * **Cyclophosphamide** * **Ifosfamide** * **Etoposide** * **Doxorubicin (Adriamycin):** An anthracycline that is a cornerstone in treating both Ewing’s and Osteosarcoma (Option A). * **Topotecan:** A Topoisomerase I inhibitor often used in second-line or salvage therapy for recurrent/refractory Ewing’s Sarcoma (Option C). **High-Yield Clinical Pearls for NEET-PG:** * **Genetics:** Characterized by the **t(11;22)** translocation, leading to the **EWS-FLI1** fusion gene. * **Radiology:** Classic **"Onion-peel"** periosteal reaction. * **Histology:** Small round blue cells that are **PAS positive** (due to cytoplasmic glycogen) and express **CD99 (MIC-2).** * **Site:** Most common in the diaphysis of long bones (Femur is most common). * **Prognosis:** The most important prognostic factor is the presence of metastasis at the time of diagnosis (Lungs and Bone marrow are common sites).

Q: Which of the following conditions is considered a premalignant condition for secondary osteosarcoma?

All of the above. **Explanation:** Secondary osteosarcoma refers to an osteosarcoma that arises from a pre-existing benign bone lesion or underlying bone pathology. Unlike primary osteosarcoma, which typically occurs in adolescents, secondary osteosarcoma usually presents in older adults (40–60+ years). **Why "All of the above" is correct:** Each of the listed conditions carries a documented risk of malignant transformation into a sarcoma, most commonly osteosarcoma or chondrosarcoma. * **Paget’s Disease (Option A):** This is the most common cause of secondary osteosarcoma in the elderly. Chronic high bone turnover leads to genetic mutations; approximately 1% of patients with extensive Paget’s disease develop osteosarcoma (often involving the pelvis, femur, or humerus). * **Enchondromatosis (Ollier’s Disease/Maffucci Syndrome) (Option B):** While solitary enchondromas rarely turn malignant, multiple enchondromas carry a significant risk (up to 25–30%) of transforming into secondary chondrosarcoma or, less commonly, osteosarcoma. * **Diaphyseal Aclasis (Hereditary Multiple Exostoses) (Option C):** This condition involves multiple osteochondromas. There is a roughly 1–5% risk of the cartilage cap undergoing malignant transformation into a secondary sarcoma. **High-Yield Clinical Pearls for NEET-PG:** * **Post-Radiation:** Prior radiotherapy is another major risk factor for secondary osteosarcoma (latency period of 5–10 years). * **Prognosis:** Secondary osteosarcomas generally have a **poorer prognosis** and a worse response to chemotherapy compared to primary osteosarcomas. * **Radiological Sign:** A sudden increase in pain or a rapid increase in the size of a stable lesion in these conditions should raise immediate suspicion of malignant transformation.

Q: Regarding bone tumors, which of the following statements are true or false? - Most common malignant tumor of bone is metastases. - Most common primary malignant bone tumor is multiple myeloma. - Codman triangle is specific for osteosarcoma. - IOC for skeletal metastases is CT scan. - Blow out bone metastases are seen in renal cell carcinoma.

True, True, False, False, True. ### Explanation This question tests fundamental concepts in musculoskeletal oncology, a high-yield area for NEET-PG. 1. **Most common malignant tumor of bone is metastases (True):** Secondary tumors (metastases) are far more frequent than primary bone malignancies, especially in adults. 2. **Most common primary malignant bone tumor is multiple myeloma (True):** While Osteosarcoma is the most common *non-hematological* primary bone tumor, **Multiple Myeloma** (a plasma cell dyscrasia) is the most common primary malignancy of the bone overall. 3. **Codman triangle is specific for osteosarcoma (False):** The Codman triangle is a type of aggressive periosteal reaction. While classic for Osteosarcoma, it is **not specific**; it can be seen in Ewing’s sarcoma, osteomyelitis, or even subperiosteal hemorrhage. 4. **IOC for skeletal metastases is CT scan (False):** The Investigation of Choice (IOC) for screening skeletal metastases is **Technetium-99m Bone Scan** (high sensitivity). However, **MRI** is the most sensitive for early marrow changes. CT is used primarily for assessing cortical integrity or guiding biopsies. 5. **Blow out bone metastases are seen in renal cell carcinoma (True):** "Blow-out" or expansile lytic lesions are characteristic of **Renal Cell Carcinoma (RCC)** and **Thyroid Carcinoma** metastases. **High-Yield Clinical Pearls for NEET-PG:** * **Sunburst appearance:** Highly suggestive of Osteosarcoma. * **Onion-skin appearance:** Characteristic of Ewing’s Sarcoma. * **Osteoblastic (Sclerotic) Metastases:** Most common in Prostate Cancer. * **Osteolytic Metastases:** Most common in Lung, Breast, and RCC. * **Bone Scan "Cold" Lesions:** Multiple Myeloma and occasionally RCC (due to purely lytic nature).

Q: Which of the following is NOT a non-neoplastic lesion that simulates a bone tumor?

Hurler syndrome. ### Explanation In Orthopaedics, certain non-neoplastic conditions are termed **"tumor-like lesions"** because they mimic the clinical or radiological appearance of true bone neoplasms. **Why Hurler Syndrome is the Correct Answer:** **Hurler syndrome (Mucopolysaccharidosis Type I)** is a systemic lysosomal storage disorder caused by a deficiency of the enzyme alpha-L-iduronidase. While it causes significant skeletal abnormalities (collectively known as *dysostosis multiplex*, such as J-shaped sella or ovoid vertebrae), it presents as a **generalized skeletal dysplasia** rather than a localized lesion that simulates a bone tumor. It does not typically enter the differential diagnosis for a solitary bone tumor. **Analysis of Incorrect Options:** * **Fibrous Dysplasia:** A classic "tumor-like lesion" where normal bone is replaced by fibrous tissue and immature bone. Radiologically, it presents as a "ground-glass" appearance and can easily be mistaken for a neoplastic process like an osteoid osteoma or low-grade sarcoma. * **Bone Island (Enostosis):** A focus of mature compact bone within the cancellous bone. It mimics a small osteoma or a sclerotic metastasis (like from prostate cancer) on X-ray. * **Bone Infarct:** Medullary bone infarction (osteonecrosis) can present with peripheral calcification and "smoke-up-the-chimney" appearance, often mimicking an enchondroma or a low-grade chondrosarcoma. **NEET-PG High-Yield Pearls:** * **Common Tumor Mimickers:** Remember the mnemonic **"FAME"** (Fibrous dysplasia, Aneurysmal bone cyst, Metaphyseal fibrous defect/NOF, Enchondroma/Eosinophilic granuloma). * **Brown Tumor:** A non-neoplastic lesion caused by **Hyperparathyroidism**; it is a classic "pseudotumor" that disappears once the underlying endocrine issue is treated. * **Myositis Ossificans:** A post-traumatic soft tissue lesion that can mimic an osteosarcoma due to rapid growth and peripheral mineralization.

Question 1

Which of the following is NOT TRUE about aneurysmal bone cyst?

Accepted Answer

Diagnosis is by FNAC

Answer

Expansile, blood-filled cyst

Answer

Most common in the upper end of the tibia

Answer

Is a pseudocyst

Question 2

An 8-year-old child presented with pain at the shoulder and arm. An X-ray reveals a uniform, well-defined lucent lesion at the metaphysis. What is the most likely diagnosis?

Accepted Answer

Simple bone cyst

Answer

Aneurysmal bone cyst

Answer

Giant cell tumor

Answer

Osteoid osteoma

Question 3

What is true about fibrous dysplasia?

Accepted Answer

Monostotic fibrous dysplasia is more commonly seen in the femur.

Answer

Polyostotic fibrous dysplasia manifests in the third decade.

Answer

Biopsy shows a chicken wire appearance.

Answer

X-ray shows patchy calcification.

Question 4

A 8-year-old male child presented with complaints of pain and swelling in the right distal femur for 5 months, along with intermittent fever, significant weight loss, and loss of appetite. Lab studies revealed anemia, leukocytosis, and elevated ESR & LDH. There was no history of trauma. Which of the following chromosomal abnormalities is characteristic of this lesion?

Accepted Answer

t(11:22)

Answer

t(15:17)

Answer

t(6:6)

Answer

t(8:21)

Question 5

What is the most common site for vertebral cancer?

Accepted Answer

Thoracic

Answer

Cervical

Answer

Lumbosacral

Answer

Cervicodorsal

Question 6

Chemotherapy of Ewing's sarcoma includes all except?

Accepted Answer

5-Fluorouracil

Answer

Doxorubicin

Answer

Dactinomycin

Answer

Topotecan

Question 7

Which of the following conditions is considered a premalignant condition for secondary osteosarcoma?

Accepted Answer

All of the above

Answer

Paget's disease

Answer

Enchondromatosis

Answer

Diaphyseal aclasis

Question 8

Which tumors are known to produce expansile bony metastases?

Accepted Answer

All the above

Answer

Renal cell carcinoma

Answer

Thyroid carcinoma

Answer

Melanoma

Question 9

Regarding bone tumors, which of the following statements are true or false?

- Most common malignant tumor of bone is metastases.
- Most common primary malignant bone tumor is multiple myeloma.
- Codman triangle is specific for osteosarcoma.
- IOC for skeletal metastases is CT scan.
- Blow out bone metastases are seen in renal cell carcinoma.

Accepted Answer

True, True, False, False, True

Answer

False, True, False, False, True

Answer

True, True, True, False, False

Answer

False, False, False, False, True

Question 10

Which of the following is NOT a non-neoplastic lesion that simulates a bone tumor?

Accepted Answer

Hurler syndrome

Answer

Fibrous dysplasia

Answer

Bone island

Answer

Bone infarct

Bone Tumors — MCQs

Bone Tumors — MCQs

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