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10. Pathology and Oncology MCQs

Practice Set 196 of 351

This practice set contains high-yield board review questions covering key concepts in 10. Pathology and Oncology. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 3901

Topic: 10. Pathology and Oncology

In patients with osteosarcoma, what is the most significant prognostic factor?

. Patient age at diagnosis.
. Tumor size.
. Location of the primary tumor.
. Presence of metastatic disease at diagnosis.
. Response to neoadjuvant chemotherapy (histologic necrosis).

Correct Answer & Explanation

. Presence of metastatic disease at diagnosis.

Explanation

The presence of metastatic disease at the time of diagnosis is the single most significant prognostic factor for osteosarcoma. Patients who present with metastatic disease have a significantly worse prognosis than those with localized disease. While patient age, tumor size, and location all influence prognosis, and response to neoadjuvant chemotherapy is crucial for treatment planning and also prognostic, the presence of macroscopic metastases at initial presentation remains the most powerful predictor of poor outcome.

Question 3902

Topic: 10. Pathology and Oncology

A 65-year-old male presents with persistent upper back pain for 6 months. He has a history of smoking and chronic obstructive pulmonary disease (COPD). X-rays show vertebral body collapse at T8. What is the most important initial investigation to rule out a pathological fracture?

. Bone mineral density (BMD) scan.
. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP).
. MRI of the thoracic spine with contrast.
. Tumor markers (e.g., PSA, CA-125).
. CT scan of the chest, abdomen, and pelvis.

Correct Answer & Explanation

. MRI of the thoracic spine with contrast.

Explanation

While a BMD scan is important for osteoporosis assessment and ESR/CRP for infection, and tumor markers could be relevant if a specific cancer is suspected, the most important initial investigation to differentiate an osteoporotic compression fracture from a pathological fracture (e.g., metastatic disease or infection) in a patient with a smoking history (lung cancer risk) and chronic back pain is an MRI of the thoracic spine with contrast. MRI can accurately visualize soft tissue abnormalities, spinal cord compression, and differentiate benign from malignant or infectious causes of vertebral collapse, which plain X-rays cannot. A CT scan of chest/abdomen/pelvis may be part of a full metastatic workup if malignancy is highly suspected, but MRI directly addresses the vertebral lesion.

Question 3903

Topic: 10. Pathology and Oncology

What is the most common primary site for metastatic bone disease that causes osteoblastic (sclerotic) lesions?

. Lung.
. Kidney.
. Thyroid.
. Prostate.
. Breast.

Correct Answer & Explanation

. Prostate.

Explanation

Prostate cancer is classically known for producing osteoblastic (sclerotic) metastases to bone. While breast cancer can produce mixed lytic and blastic lesions, and lung and kidney cancer typically produce lytic lesions, prostate cancer is the most common cause of purely osteoblastic metastases. Thyroid cancer metastases are usually lytic. Understanding the typical radiographic appearance of metastases from different primary sites is crucial for orthopedic oncologists.

Question 3904

Topic: 10. Pathology and Oncology

A 68-year-old male with a history of hypertension and benign prostatic hyperplasia presents to the orthopedic clinic with left groin pain radiating to his knee. Examination reveals pain on passive hip flexion and internal rotation. A potential diagnosis is hip osteoarthritis. Which of the following is an important consideration in this patient's history that may mask or mimic musculoskeletal pain or be an important differential?

. Previous knee injury.
. Chronic low back pain.
. Urinary frequency and nocturia.
. Peripheral vascular disease.
. History of gout.

Correct Answer & Explanation

. Urinary frequency and nocturia.

Explanation

While all listed options can be relevant, urinary frequency and nocturia related to benign prostatic hyperplasia (BPH) are important to consider because referred pain from the bladder or prostate can sometimes mimic or exacerbate hip/groin pain. While not directly a musculoskeletal cause, it's crucial for an orthopedic examiner to consider non-musculoskeletal sources of pain, especially in the context of urological symptoms in the region. Chronic low back pain and peripheral vascular disease are also important differentials or comorbidities for leg pain, but the question specifically asks about a consideration related to the patient's history of BPH. Previous knee injury and gout are musculoskeletal conditions, not mimicking or masking issues related to BPH.

Question 3905

Topic: 10. Pathology and Oncology

A 60-year-old male with a history of prostate cancer treated with androgen deprivation therapy presents with a new, rapidly progressing pathological fracture of the distal femur. Biopsy confirms metastatic adenocarcinoma. Which of the following systemic treatments is most appropriate to consider in this scenario?

. Bisphosphonates.
. Denosumab.
. Chemotherapy.
. Radiation therapy.
. All of the above.

Correct Answer & Explanation

. All of the above.

Explanation

In a patient with metastatic prostate cancer, a pathological fracture, and failure of prior hormonal therapy, a multi-modal approach is typically warranted. Bisphosphonates (like zoledronic acid) and Denosumab are bone-modifying agents used to reduce skeletal-related events (SREs), including fractures. Chemotherapy (e.g., docetaxel, cabazitaxel) is indicated for castration-resistant prostate cancer. Radiation therapy is crucial for local pain control and fracture stabilization. Therefore, all these systemic and local treatments may be considered as part of a comprehensive management plan for this advanced metastatic disease, in conjunction with surgical fixation of the fracture. The question asks for systemic treatments to consider, and both bone-modifying agents and chemotherapy fit this description, along with radiation for local control. So, 'All of the above' is the most comprehensive answer in the context of considering treatment options.

Question 3906

Topic: 10. Pathology and Oncology

Which of the following spinal tumors is most commonly associated with a 'soap bubble' appearance on X-ray and is often found in the sacrum?

. Osteosarcoma.
. Ewing's sarcoma.
. Chordoma.
. Chondrosarcoma.
. Multiple myeloma.

Correct Answer & Explanation

. Chordoma.

Explanation

Chordomas are rare, slow-growing malignant bone tumors arising from remnants of the notochord. They are most commonly found at the ends of the axial skeleton, specifically the sacrococcygeal region (50-60%) and the clivus (30-35%), and less frequently in the mobile spine. Radiographically, they often present as a lytic, destructive lesion with a characteristic 'soap bubble' or 'bubbly' appearance due to calcification and mucoid degeneration within the tumor. Osteosarcoma and Ewing's sarcoma are more aggressive and usually found in long bones or other parts of the spine. Chondrosarcoma is cartilaginous, and multiple myeloma presents as punched-out lytic lesions.

Question 3907

Topic: 10. Pathology and Oncology

A 60-year-old male with a history of lung cancer undergoing chemotherapy develops severe mid-back pain that is worse at night and unrelieved by rest. MRI shows a destructive lesion at T7 with epidural compression. What is the most appropriate initial management step for the pain?

. Immediate surgical decompression.
. Start NSAIDs and muscle relaxants.
. Administer high-dose corticosteroids and evaluate for radiation/surgical options.
. Initiate aggressive opioid therapy.
. Prescribe physical therapy.

Correct Answer & Explanation

. Administer high-dose corticosteroids and evaluate for radiation/surgical options.

Explanation

In a patient with known lung cancer, a new destructive vertebral lesion with epidural compression and pain worsening at night (red flag for malignancy) strongly suggests metastatic spinal cord compression (MSCC). The most appropriate initial management for suspected MSCC, particularly with pain, is to administer high-dose corticosteroids (e.g., dexamethasone) immediately to reduce peritumoral edema and alleviate pain and neurological compromise, while simultaneously evaluating for definitive treatment options like radiation therapy or urgent surgical decompression. NSAIDs and muscle relaxants are insufficient. Opioids are for pain control but don't address the underlying compression. Physical therapy is contraindicated until stability is assessed and compression relieved. Immediate surgery may be indicated if there's rapid neurological deterioration, but steroids are typically the first-line medical intervention while further workup and planning occur.

Question 3908

Topic: 10. Pathology and Oncology

A 40-year-old male presents with chronic cough, hemoptysis, and chest pain. Imaging reveals a mass in the apex of the right lung. Orthopedically, what is a specific neurological sign you would look for that is highly suggestive of local tumor extension?

. Diminished biceps reflex.
. Foot drop.
. Horner's syndrome (ptosis, miosis, anhidrosis).
. Sensory loss in the L5 dermatome.
. Wrist drop.

Correct Answer & Explanation

. Horner's syndrome (ptosis, miosis, anhidrosis).

Explanation

A mass in the apex of the lung is characteristic of a Pancoast tumor. Pancoast tumors are known to invade the brachial plexus (causing arm pain and neurological deficits in the C8-T1 distribution) and the sympathetic chain. Involvement of the sympathetic chain specifically causes Horner's syndrome, which is characterized by ipsilateral ptosis (drooping eyelid), miosis (constricted pupil), and anhidrosis (absence of sweating) of the face. This neurological triad is highly suggestive of local tumor extension from an apical lung mass. The other neurological signs are related to different nerve roots or peripheral nerves and are not specific to Pancoast tumor in this context.

Question 3909

Topic: 10. Pathology and Oncology

What is the most common primary malignant bone tumor in children and adolescents?

. Chondrosarcoma
. Osteosarcoma
. Ewing's sarcoma
. Multiple myeloma
. Fibrosarcoma

Correct Answer & Explanation

. Osteosarcoma

Explanation

Osteosarcoma is the most common primary malignant bone tumor in children and adolescents, typically peaking in the second decade of life. Ewing's sarcoma is the second most common. Chondrosarcoma and fibrosarcoma are more common in adults. Multiple myeloma is a plasma cell dyscrasia primarily affecting older adults.

Question 3910

Topic: 10. Pathology and Oncology

A 16-year-old male presents with worsening pain and swelling in his distal femur for the past 3 months. Radiographs show a lytic lesion with a 'sunburst' periosteal reaction and Codman's triangle. What is the most likely diagnosis?

. Osteochondroma
. Enchondroma
. Giant cell tumor
. Osteosarcoma
. Ewing's sarcoma

Correct Answer & Explanation

. Osteosarcoma

Explanation

The patient's age (adolescent), location (distal femur), and classic radiographic findings (lytic lesion with 'sunburst' periosteal reaction and Codman's triangle) are highly suggestive of osteosarcoma, the most common primary malignant bone tumor in this age group. Ewing's sarcoma can also show aggressive features but often presents with an 'onion skin' periosteal reaction. Osteochondroma and enchondroma are benign. Giant cell tumor typically occurs in young adults and is epiphyseal.

Question 3911

Topic: 10. Pathology and Oncology

A 75-year-old female presents with acute severe back pain after a minor fall. Radiographs show a compression fracture of the T12 vertebral body. She has no neurological deficits. Which of the following is the most appropriate initial management?

. Emergent surgical decompression and fusion
. Vertebroplasty or kyphoplasty within 24 hours
. Opioid analgesics, activity modification, and bracing for pain control
. MRI to rule out spinal cord compression immediately
. Biopsy of the vertebra to rule out malignancy

Correct Answer & Explanation

. Opioid analgesics, activity modification, and bracing for pain control

Explanation

For an osteoporotic compression fracture without neurological deficits, the initial management is typically conservative, focusing on pain control, activity modification, and possibly bracing. Opioid analgesics are often needed initially. Vertebroplasty or kyphoplasty may be considered if pain is refractory to conservative measures, but it is not an emergent 'within 24 hours' procedure. MRI is indicated if there are neurological symptoms or suspicion of malignancy, but not routinely for an uncomplicated osteoporotic fracture. Biopsy is not the immediate first step unless malignancy is highly suspected (e.g., history of cancer, atypical fracture pattern).

Question 3912

Topic: 10. Pathology and Oncology

A 60-year-old male with a history of prostate cancer presents with new onset severe low back pain and bilateral lower extremity weakness. MRI shows a large epidural mass compressing the spinal cord at T10. What is the most appropriate immediate management?

. Start chemotherapy
. Administer high-dose intravenous corticosteroids
. Emergent surgical decompression
. Radiation therapy
. Physical therapy for strengthening

Correct Answer & Explanation

. Administer high-dose intravenous corticosteroids

Explanation

For patients with suspected or confirmed malignant spinal cord compression (SCC), the immediate priority is to reduce edema and inflammation around the spinal cord to preserve neurological function. High-dose intravenous corticosteroids (e.g., dexamethasone) are the mainstay of initial treatment. This provides temporary relief and buys time for definitive treatment. While emergent surgical decompression or radiation therapy will be necessary, corticosteroid administration is the immediate first step prior to these interventions and often initiated even before confirmatory imaging if SCC is highly suspected. Chemotherapy and physical therapy are not immediate treatments for acute SCC.

Question 3913

Topic: 10. Pathology and Oncology

A 1-year-old child presents with an inability to bear weight on the left leg, fever, and localized swelling and warmth over the distal tibia. Radiographs show periosteal reaction and lucency in the metaphysis. What is the most likely diagnosis?

. Toddler's fracture
. Osteosarcoma
. Ewing's sarcoma
. Acute hematogenous osteomyelitis
. Rickets

Correct Answer & Explanation

. Acute hematogenous osteomyelitis

Explanation

The clinical presentation (fever, localized pain, swelling, refusal to bear weight) and radiographic findings (periosteal reaction, lucency in metaphysis) in a young child are highly suggestive of acute hematogenous osteomyelitis. The metaphysis is a common site due to its rich blood supply and sluggish flow. Toddler's fracture is a non-displaced spiral fracture of the tibia, typically without fever. Osteosarcoma and Ewing's sarcoma are less common at this age and have different radiographic features (though some overlap). Rickets is a metabolic bone disease affecting growth plates, not an acute infectious process.

Question 3914

Topic: 10. Pathology and Oncology

What is the most common benign bone tumor?

. Osteoid osteoma
. Enchondroma
. Osteochondroma
. Fibrous dysplasia
. Giant cell tumor

Correct Answer & Explanation

. Osteochondroma

Explanation

Osteochondroma is by far the most common benign bone tumor, accounting for 20-50% of all benign bone tumors and 10-15% of all bone tumors. It is characterized by an exostosis with a cartilaginous cap. Enchondroma and osteoid osteoma are also common but less frequent than osteochondroma.

Question 3915

Topic: Bone Tumors

A 14-year-old boy presents with progressive knee pain and swelling over the past 2 months. A representative imaging study of the distal femur is shown below.

Assuming the radiograph demonstrates a destructive metaphyseal lesion with a 'sunburst' periosteal reaction and Codman's triangle, what is the most likely diagnosis?

. Osteosarcoma
. Ewing Sarcoma
. Giant Cell Tumor
. Chondrosarcoma
. Osteoid Osteoma

Correct Answer & Explanation

. Osteosarcoma

Explanation

The clinical presentation of a teenager with a destructive, bone-forming metaphyseal lesion demonstrating aggressive periosteal reactions (like a sunburst pattern or Codman's triangle) is highly characteristic of conventional osteosarcoma. Giant cell tumors are typically epiphyseal, and Ewing sarcoma usually presents as a permeative diaphyseal lesion with 'onion-skin' periosteal reaction.

Question 3916

Topic: 10. Pathology and Oncology

A 35-year-old male presents with a deep-seated, painful soft tissue mass in his thigh. Core needle biopsy confirms Synovial Sarcoma. Which of the following chromosomal translocations is uniquely diagnostic for this tumor?

. t(11;22)
. t(X;18)
. t(12;16)
. t(2;13)
. t(9;22)

Correct Answer & Explanation

. t(X;18)

Explanation

Synovial sarcoma is characterized by the t(X;18)(p11;q11) translocation, which results in the SYT-SSX fusion gene. t(11;22) is seen in Ewing sarcoma; t(12;16) in myxoid liposarcoma; t(2;13) in alveolar rhabdomyosarcoma; and t(9;22) in chronic myelogenous leukemia (Philadelphia chromosome).

Question 3917

Topic: 10. Pathology and Oncology

A 72-year-old man presents with severe back pain and is found to have diffuse osteoblastic lesions in his lumbar spine. A biopsy is consistent with metastatic prostate cancer. Which factor, secreted by the prostate tumor cells, primarily mediates this characteristic osteoblastic response?

. Parathyroid hormone-related peptide (PTHrP)
. Endothelin-1 (ET-1)
. Receptor Activator of Nuclear factor Kappa-B Ligand (RANKL)
. Tumor Necrosis Factor-alpha (TNF-a)
. Interleukin-6 (IL-6)

Correct Answer & Explanation

. Endothelin-1 (ET-1)

Explanation

Metastatic prostate cancer is classically associated with osteoblastic (bone-forming) bone lesions. Prostate cancer cells secrete Endothelin-1 (ET-1), which strongly stimulates osteoblast proliferation and bone formation. In contrast, tumors like breast or lung cancer typically secrete PTHrP, leading to osteolytic lesions.

Question 3918

Topic: 10. Pathology and Oncology
Which of the following pro-inflammatory cytokines plays a central role in the initial systemic response to infection and trauma, often leading to the development of SIRS?
. Interleukin-10 (IL-10)
. Transforming Growth Factor-beta (TGF-β)
. Tumor Necrosis Factor-alpha (TNF-α)
. Interleukin-4 (IL-4)
. Granulocyte-Colony Stimulating Factor (G-CSF)

Correct Answer & Explanation

. Tumor Necrosis Factor-alpha (TNF-α)

Explanation

TNF-α, along with IL-1β and IL-6, are key early pro-inflammatory cytokines that initiate and propagate the systemic inflammatory response in sepsis and severe trauma. They mediate fever, acute phase reactant production, endothelial activation, and leukocyte recruitment. IL-10 and IL-4 are primarily anti-inflammatory cytokines. TGF-β has pleiotropic effects but is not a primary initiator of acute SIRS. G-CSF primarily stimulates neutrophil production.

Question 3919

Topic: 10. Pathology and Oncology

A 30-year-old male with an open fracture develops sepsis and subsequently hyperthermia (40°C), muscle rigidity, and rhabdomyolysis after receiving succinylcholine during intubation. This presentation is most consistent with which rare but life-threatening condition?

. Neuroleptic Malignant Syndrome
. Serotonin Syndrome
. Malignant Hyperthermia
. Heatstroke
. Tetanus

Correct Answer & Explanation

. Malignant Hyperthermia

Explanation

The combination of severe hyperthermia, muscle rigidity, and rhabdomyolysis, specifically triggered by succinylcholine (a depolarizing neuromuscular blocker) in a susceptible individual, is classic for Malignant Hyperthermia (MH). This is a pharmacogenetic disorder of skeletal muscle. While sepsis can cause fever, this specific constellation of symptoms with succinylcholine exposure points strongly to MH. The other conditions have different triggers and/or clinical presentations.

Question 3920

Topic: 10. Pathology and Oncology

A 55-year-old patient is diagnosed with a high-grade leiomyosarcoma of the proximal thigh. Preoperative imaging has confirmed no distant metastases. When planning definitive surgical resection, which of the following 'tumor surgery principles' is most critical to prevent local recurrence and achieve a curative outcome?

. Performing a wide excisional biopsy prior to definitive resection to confirm histology.
. Ensuring negative margins by resecting the tumor en bloc with a cuff of normal tissue.
. Administering adjuvant chemotherapy immediately post-resection.
. Utilizing electrocautery sparingly to avoid thermal necrosis of surrounding tissues.
. Prioritizing limb salvage over radical resection whenever possible.

Correct Answer & Explanation

. Ensuring negative margins by resecting the tumor en bloc with a cuff of normal tissue.

Explanation

The fundamental principle of oncologic surgery, particularly for high-grade sarcomas, is to achieve negative (R0) surgical margins. This is encapsulated by the principle 'not cutting through the tumor' and 'resecting by dissecting from periphery to center, always in normal tissue surrounding the tumor.' Ensuring negative margins by resecting the tumor en bloc with a cuff of normal tissue (wide resection) is the most critical factor for preventing local recurrence and maximizing the chance of cure, directly aligning with the provided general 'tumor surgery principles.' While neoadjuvant/adjuvant chemotherapy, preoperative biopsy, and limb salvage are important considerations, achieving clear margins is the cornerstone of local tumor control. A wide excisional biopsy is inappropriate; an incisional or core needle biopsy is done first.

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