Pediatric Oncology Imaging Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Pediatric Oncology Imaging. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Pediatric Oncology Imaging Indian Medical PG Question 1: Which of the following is not true about osteosarcoma?
- A. Seen in the metaphyseal region of the long bones
- B. Lung metastasis is common
- C. Secondary osteosarcoma is seen in older age groups
- D. Most commonly arises in the epiphyseal region (Correct Answer)
Pediatric Oncology Imaging Explanation: ***Most commonly arises in the epiphyseal region***
- This statement is **FALSE** - osteosarcoma most commonly arises in the **metaphyseal region** of long bones, particularly around the knee (distal femur, proximal tibia) and proximal humerus [1].
- The metaphysis is the region where bone growth is most active, which explains why osteosarcoma preferentially occurs there.
- The epiphysis (growth plate region) is **not** the typical location for osteosarcoma.
*Seen in the metaphyseal region of the long bones*
- This is **TRUE** - osteosarcoma characteristically arises in the **metaphyseal regions** of long bones, especially around the knee and proximal humerus where growth is most active [1].
*Lung metastasis is common*
- This is **TRUE** - the lungs are the most common site of distant metastasis in osteosarcoma, occurring in up to 80% of patients who develop metastatic disease [1].
- Pulmonary metastasis significantly impacts prognosis and treatment [1].
*Secondary osteosarcoma is seen in older age groups*
- This is **TRUE** - while primary osteosarcoma affects children and young adults (peak 10-20 years), **secondary osteosarcoma** occurs in older patients, typically arising in association with Paget's disease, prior radiation therapy, or bone infarcts [1].
**References:**
[1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1200-1202.
Pediatric Oncology Imaging Indian Medical PG Question 2: A young girl presented with swelling of right thigh, with history of trauma 2 months back. Now she presents with swelling at mid-shaft of femur & low grade fever. ESR is mildly raised. X-ray shows a laminated periosteal reaction. Next line of investigation would be:
- A. MRI (Correct Answer)
- B. Bone scan
- C. Blood count & CRP
- D. Biopsy
Pediatric Oncology Imaging Explanation: ***MRI***
- An **MRI** is the most appropriate next step as it provides excellent detailed imaging of soft tissues and bone marrow, allowing better characterization of the **periosteal reaction**, identifying abscesses, and assessing the extent of bone involvement, crucial for differentiating between infection and tumor.
- The presence of a **laminated periosteal reaction** (like an "onion peel") on X-ray, in conjunction with localized swelling and low-grade fever, is highly suggestive of subacute osteomyelitis or even some bone tumors like Ewing sarcoma, for which MRI is superior for defining the extent.
*Bone scan*
- A **bone scan** (technetium-99m) is sensitive for detecting increased bone turnover, which occurs in infections and tumors, but it is **non-specific**, meaning it cannot differentiate between these conditions.
- While it could show increased uptake in the affected area, it would not provide the anatomical detail needed to characterize the lesion or guide further management as effectively as an MRI.
*Blood count & CRP*
- A **blood count and CRP** would provide information on systemic inflammation (e.g., leukocytosis, elevated CRP for infection), but these are **non-specific**.
- While ESR is already mildly raised, these blood tests would confirm generalized inflammation but **cannot localize or characterize the lesion** in the bone, offering little diagnostic value for the specific problem at this stage without imaging.
*Biopsy*
- A **biopsy** is an invasive procedure and is typically performed after initial imaging studies like X-ray and MRI have characterized the lesion to guide the biopsy site and help determine the nature of the condition (e.g., infection vs. tumor).
- Performing a biopsy as the immediate next step without detailed imaging to assess the extent and nature of the lesion would be premature and potentially less effective in diagnosis.
Pediatric Oncology Imaging Indian Medical PG Question 3: Investigation of choice for leptomeningeal carcinomatosis:
- A. Gd enhanced MRI (Correct Answer)
- B. CT scan
- C. SPECT
- D. PET
Pediatric Oncology Imaging Explanation: ***Gd enhanced MRI***
- **Gadolinium-enhanced MRI** is the investigation of choice for **leptomeningeal carcinomatosis** as it can visualize the subtle nodular or linear enhancement along the leptomeninges, indicating tumor dissemination.
- It offers superior **soft tissue contrast** and spatial resolution compared to CT, enabling detection of small lesions and accurate mapping of disease extent.
*CT scan*
- A **CT scan** has limited sensitivity for detecting leptomeningeal involvement due to poor contrast resolution of soft tissues and the dura/arachnoid spaces.
- It might show hydrocephalus or large tumor deposits, but subtle leptomeningeal enhancement is often missed.
*SPECT*
- **Single photon emission computed tomography (SPECT)** is primarily used for functional imaging and is not the investigation of choice for anatomical visualization of leptomeningeal carcinomatosis.
- Its resolution is too low to detect the fine structural changes associated with leptomeningeal spread.
*PET*
- **Positron emission tomography (PET)**, often combined with CT, identifies metabolically active tumor cells and can detect diffuse metastatic disease.
- While useful for overall cancer staging and identifying primary lesions, it is less effective than gadolinium-enhanced MRI for directly visualizing the morphology and enhancement patterns of leptomeningeal carcinomatosis due to limited spatial resolution in the CSF spaces.
Pediatric Oncology Imaging Indian Medical PG Question 4: Not seen in Neuroblastoma is -
- A. Bone involvement
- B. Splenomegaly (Correct Answer)
- C. Diarrhoea
- D. Proptosis
Pediatric Oncology Imaging Explanation: ***Splenomegaly***
- **Splenomegaly is NOT a typical feature of neuroblastoma**, making this the correct answer to this negation question.
- Neuroblastoma commonly metastasizes to **bone marrow, liver, lymph nodes, and bones**, but **rarely involves the spleen**.
- Unlike lymphomas and leukemias where splenomegaly is common, neuroblastoma's metastatic pattern typically spares the spleen.
*Bone involvement*
- **Bone metastases are common in neuroblastoma** (60-70% of advanced cases), particularly in stage 4 disease.
- Presents with bone pain, pathologic fractures, and lytic lesions on imaging.
- Hematogenous dissemination from the neural crest origin allows frequent skeletal involvement.
*Diarrhoea*
- **Secretory diarrhea occurs in 7-9% of neuroblastoma cases** due to vasoactive intestinal peptide (VIP) secretion.
- Presents as severe watery diarrhea with hypokalemia and metabolic acidosis.
- Part of the opsoclonus-myoclonus-ataxia syndrome or as an isolated paraneoplastic phenomenon.
*Proptosis*
- **Orbital metastases cause proptosis and periorbital ecchymoses** ("raccoon eyes"), a classic presentation.
- Indicates advanced disease with skull and facial bone involvement.
- Seen in approximately 10-15% of cases at presentation, particularly in younger children.
Pediatric Oncology Imaging Indian Medical PG Question 5: Most common tumor in children is -
- A. Wilms tumor
- B. Lymphoma
- C. Leukemia (Correct Answer)
- D. Neuroblastoma
Pediatric Oncology Imaging Explanation: ***Leukemia***
- **Leukemia** is the most common form of cancer in children, accounting for approximately 30% of all childhood cancers.
- Among leukemias, **acute lymphoblastic leukemia (ALL)** is the most prevalent type in pediatric patients.
*Wilm's tumor*
- **Wilms' tumor** (nephroblastoma) is a kidney cancer and is one of the most common solid tumors in children.
- While significant, it is less common overall than leukemia.
*Lymphoma*
- **Lymphoma** is a cancer of the lymphatic system and is the third most common type of cancer in children.
- It includes Hodgkin and non-Hodgkin lymphomas.
*Neuroblastoma*
- **Neuroblastoma** is a cancer that develops from immature nerve cells found in several areas of the body, often in the adrenal glands.
- It is one of the most common cancers in infants but is less common overall in the pediatric population compared to leukemia.
Pediatric Oncology Imaging Indian Medical PG Question 6: Investigation of choice for the diagnosis of congenital hypertrophic pyloric stenosis is:
- A. USG (Correct Answer)
- B. Barium meal
- C. Barium meal follow through
- D. CT scan with contrast
Pediatric Oncology Imaging Explanation: ***USG***
- **Ultrasound** is the preferred initial imaging modality due to its non-invasiveness, lack of radiation, and high accuracy in visualizing the thickened pyloric muscle.
- The classic ultrasound findings include a **pyloric muscle thickness** of ≥ 4 mm and a **pyloric channel length** of ≥ 14 mm.
*Barium meal*
- While a barium meal can show findings like the "string sign" or "shoulder sign," it involves **radiation exposure** and is generally considered a second-line investigation.
- Its diagnostic accuracy is good, but it is less convenient and riskier than ultrasound for this condition.
*Barium meal follow through*
- This procedure tracks barium through the entire gastrointestinal tract, which is **excessive and unnecessary** for diagnosing pyloric stenosis, which is a localized obstruction.
- It also involves significant **radiation exposure** and a prolonged examination time.
*CT scan with contrast*
- A **CT scan** involves significant **radiation exposure** and is not typically used for diagnosing congenital hypertrophic pyloric stenosis.
- It is also less sensitive than ultrasound for visualizing the specific soft tissue changes in the pyloric muscle.
Pediatric Oncology Imaging Indian Medical PG Question 7: Parameningeal Rhabdomyosarcoma is best diagnosed by:
- A. MRI (Correct Answer)
- B. CT Scan
- C. SPECT
- D. PET
Pediatric Oncology Imaging Explanation: ***MRI***
- **Magnetic Resonance Imaging (MRI)** provides excellent soft tissue contrast, which is crucial for visualizing the extent of **parameningeal rhabdomyosarcoma** and its relationship to critical structures like the **meninges**, **brainstem**, and **cranial nerves**.
- It is superior for detecting **intracranial extension**, **bone erosion**, and assessing response to treatment, making it the preferred imaging modality for diagnosis and staging.
*CT Scan*
- **Computed Tomography (CT) scans** are good for evaluating bone involvement and calcifications but offer less detailed soft tissue resolution compared to MRI.
- While it can identify large masses, it may miss subtle extensions or involvement of the **meninges** that are readily seen on MRI.
*SPECT*
- **Single-Photon Emission Computed Tomography (SPECT)** is a nuclear medicine imaging technique primarily used to assess organ function and blood flow, often in cardiology or neurology for functional studies.
- It provides limited anatomical detail for the precise localization and characterization of soft tissue tumors like **rhabdomyosarcoma**.
*PET*
- **Positron Emission Tomography (PET) scans** are excellent for detecting metabolically active tumors, assessing disease burden, and identifying distant metastases, especially when combined with CT (**PET/CT**).
- However, while useful for staging and follow-up, it does not provide the high-resolution anatomical detail of the primary tumor's local extent and its relationship to adjacent structures as effectively as **MRI**.
Pediatric Oncology Imaging Indian Medical PG Question 8: Which of the following bone lesions is characterized by the 'fallen fragment sign,' a radiological feature seen in lytic bone lesions with fluid-filled cavities?
- A. Adamantinoma
- B. Aneurysmal bone cyst
- C. Simple bone cyst (Correct Answer)
- D. Osteosarcoma
Pediatric Oncology Imaging Explanation: ***Simple bone cyst***
- The **'fallen fragment sign'** is a **pathognomonic radiological feature** of simple bone cysts (unicameral bone cysts).
- This sign occurs when a **pathological fracture** through the cyst allows a fragment of cortical bone to fall into the fluid-filled cavity and settle dependently at the bottom, visible on upright radiographs.
- Simple bone cysts are benign, fluid-filled lesions commonly affecting the **proximal humerus and proximal femur** in children and adolescents.
*Aneurysmal bone cyst*
- This is a **benign, blood-filled, expansile lesion** with multiple septated compartments.
- Characteristic radiological feature is **fluid-fluid levels** on MRI or CT due to blood products of different densities.
- Does NOT typically demonstrate the 'fallen fragment sign' - the multi-loculated nature prevents free-floating bone fragments.
*Adamantinoma*
- This rare **malignant bone tumor** primarily affects the **tibia** and presents as a lytic lesion, often with sclerotic borders.
- It is a solid tumor that does not form simple fluid-filled cavities or demonstrate the 'fallen fragment sign.'
*Osteosarcoma*
- This is a **highly malignant bone tumor** characterized by osteoid production and bone destruction.
- Often presents with periosteal reaction like a **'sunburst' pattern or Codman's triangle**.
- It is a solid, aggressive tumor that does not form fluid-filled cavities that would exhibit a 'fallen fragment sign.'
Pediatric Oncology Imaging Indian Medical PG Question 9: In which condition is the cleavage plane sign typically observed?
- A. Parosteal osteosarcoma (Correct Answer)
- B. Ewing's sarcoma
- C. Chondrosarcoma
- D. Metastasis
Pediatric Oncology Imaging Explanation: ***Parosteal osteosarcoma***
- The **cleavage plane sign** refers to the presence of a fat-filled or fibrous plane separating the tumor from the underlying cortex, which is characteristic of **parosteal osteosarcoma**.
- This sign indicates the **juxtacortical (parosteal) growth pattern** of the tumor, which begins on the bone surface and typically grows outwards.
*Ewing's sarcoma*
- **Ewing's sarcoma** is a highly aggressive malignant bone tumor that originates in the bone marrow, often presenting with an **"onion-skin" periosteal reaction** due to its intramedullary growth.
- It does not typically exhibit a clear cleavage plane between the tumor and the cortex as it grows from within the bone.
*Chondrosarcoma*
- **Chondrosarcoma** is a malignant tumor of cartilage, often showing **popcorn-like calcifications** and endosteal scalloping, indicating its cartilaginous matrix and intramedullary growth.
- While it can be juxtacortical, it does not typically present with a distinct fat or fibrous cleavage plane from the underlying bone like parosteal osteosarcoma.
*Metastasis*
- **Bone metastases** are secondary cancers that have spread to the bone, often presenting as **lytic or blastic lesions** depending on the primary tumor type.
- These lesions typically originate within the bone marrow and invade the bone structure, rather than growing from the surface with a distinct cleavage plane.
Pediatric Oncology Imaging Indian Medical PG Question 10: What is the best investigation for diagnosis and staging of renal cell carcinoma with thrombus extending into the IVC?
- A. CT scan (Correct Answer)
- B. Angiography
- C. Colour doppler imaging
- D. IVP
Pediatric Oncology Imaging Explanation: ***CT scan***
- **CT scan** with contrast is the gold standard for diagnosing renal cell carcinoma and evaluating the extent of tumor thrombus into the **IVC**.
- It provides detailed anatomical information on the tumor, staging, and involvement of adjacent structures.
*Angiography*
- **Angiography** is an invasive procedure primarily used for mapping the vascular supply of the tumor preoperatively or for embolization, not as a primary diagnostic tool.
- It carries risks associated with contrast agents and catheterization and provides less comprehensive detail on tumor extension compared to CT.
*Colour doppler imaging*
- While useful for detecting blood flow and confirming the presence of a thrombus, **color Doppler imaging** (ultrasound) has limitations in accurately assessing the cranial extent of an IVC thrombus.
- Its diagnostic accuracy is highly operator-dependent and less reliable for deep structures like the IVC compared to CT.
*IVP*
- **Intravenous Pyelogram (IVP)** assesses the urinary tract's structure and function but has limited utility in detecting soft tissue masses like renal cell carcinoma or IVC thrombus.
- It involves radiation exposure and contrast material, and has largely been replaced by more advanced imaging techniques like CT and MRI for renal masses.
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