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10. Pathology and Oncology MCQs

Practice Set 275 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 5481

Topic: 10. Pathology and Oncology

Which of the following scenarios would MOST strongly contraindicate an open biopsy for a suspected spinal tumor, favoring percutaneous CT-guided biopsy or FNA?

. Large, easily accessible paraspinal mass
. Prior failed percutaneous biopsy
. Need for frozen section analysis to guide immediate definitive surgery
. Highly vascular lesion (e.g., suspected renal cell metastasis)
. Suspected lymphoma

Correct Answer & Explanation

. Highly vascular lesion (e.g., suspected renal cell metastasis)

Explanation

For highly vascular lesions, such as suspected renal cell carcinoma metastases, an open biopsy carries a significant risk of severe hemorrhage. In these cases, a percutaneous CT-guided biopsy, often with prior embolization, is generally preferred due to its minimally invasive nature and lower bleeding risk. While open biopsy provides a larger specimen, the risk of bleeding in a hypervascular lesion can be catastrophic. Large, accessible masses, failed percutaneous attempts, or the need for immediate surgical guidance are often indications for open biopsy. Lymphoma biopsy requires adequate tissue, which can sometimes favor open, but hypervascularity is a definite contraindication to routine open approach.

Question 5482

Topic: 10. Pathology and Oncology

What is the most common primary site for metastatic tumors to the spine in males?

. Lung
. Breast
. Prostate
. Kidney
. Thyroid

Correct Answer & Explanation

. Prostate

Explanation

In males, prostate cancer is the most common primary site for metastatic disease to the spine, often presenting with blastic lesions. Lung cancer is also very common in both sexes. In females, breast cancer is the most common primary site. Kidney and thyroid cancers also frequently metastasize to the spine but are less common overall than prostate in males.

Question 5483

Topic: 10. Pathology and Oncology

A patient with a known metastatic lesion to the spine presents with excruciating back pain unrelieved by narcotics, but no neurological deficit. Imaging shows a lytic lesion with cortical destruction but no clear instability based on SINS. What is a reasonable initial management step to address the severe pain?

. Immediate surgical decompression
. Initiate systemic chemotherapy
. Referral for radiation therapy (e.g., conventional EBRT or SBRT)
. Repeat MRI in 3 months
. Enroll in hospice care

Correct Answer & Explanation

. Referral for radiation therapy (e.g., conventional EBRT or SBRT)

Explanation

For metastatic spinal lesions causing severe pain, even without neurological deficit or clear instability, radiation therapy (either conventional external beam radiation therapy - EBRT - or stereotactic body radiation therapy - SBRT) is highly effective for pain control. Many metastatic lesions are radiosensitive, and radiation can significantly reduce tumor burden and inflammation, leading to pain relief. Immediate surgery is not indicated without neurological compromise or overt instability. Chemotherapy is systemic. Observation is inappropriate for excruciating pain. Hospice is premature if active pain management is possible.

Question 5484

Topic: Bone Tumors

Which of the following features on MRI is most characteristic of a myxopapillary ependymoma of the filum terminale?

. Large associated syrinx within the spinal cord
. Expansile lesion with multiple fluid-fluid levels
. Well-circumscribed, lobulated, enhancing lesion at the conus/filum terminale, often with peripheral hemosiderin capping due to hemorrhage
. Intradural-extramedullary location with a dural tail sign
. Intramedullary lesion with heterogeneous enhancement and associated peritumoral edema

Correct Answer & Explanation

. Well-circumscribed, lobulated, enhancing lesion at the conus/filum terminale, often with peripheral hemosiderin capping due to hemorrhage

Explanation

Myxopapillary ependymomas are typically found at the conus medullaris or filum terminale. On MRI, they are characteristically well-circumscribed, lobulated, and show strong homogeneous enhancement. A key feature is the presence of peripheral hemosiderin capping or intratumoral hemorrhage, often seen as T1/T2 signal changes due to blood products, resulting from their high vascularity and tendency to bleed. A large syrinx is more typical of higher cervical/thoracic ependymomas. Fluid-fluid levels are characteristic of ABC. Dural tail is for meningioma. Heterogeneous enhancement with peritumoral edema is less specific.

Question 5485

Topic: 10. Pathology and Oncology

An immunocompromised patient develops subacute low back pain, fever, and constitutional symptoms. MRI shows L4-L5 discitis and osteomyelitis with a paravertebral abscess. Blood cultures are negative, but a tissue biopsy reveals fungal elements. What is the most likely causative organism?

. Staphylococcus aureus
. E. coli
. Candida spp.
. Mycobacterium tuberculosis
. Brucella spp.

Correct Answer & Explanation

. Candida spp.

Explanation

In immunocompromised patients, especially those with prolonged antibiotic use, central lines, or malignancy, fungal infections (e.g., Candida spp., Aspergillus spp.) of the spine should be considered. Candida spp. are among the most common causes of fungal spinal infections in this population. The presence of fungal elements on biopsy confirms a fungal etiology. The other options are bacterial (A, B, E) or mycobacterial (D).

Question 5486

Topic: 10. Pathology and Oncology

A patient presents with subacute back pain, progressive leg weakness, and bladder dysfunction. MRI reveals an enhancing mass in the epidural space. While an abscess is suspected, what other major differential diagnosis must be ruled out?

. Multiple Sclerosis
. Disc extrusion
. Primary or metastatic spinal tumor
. Herpes Zoster
. Myasthenia Gravis

Correct Answer & Explanation

. Primary or metastatic spinal tumor

Explanation

Spinal epidural tumors, whether primary (e.g., schwannoma, meningioma, ependymoma) or metastatic, can present with very similar symptoms to a spinal epidural abscess, including back pain, progressive neurological deficits, and an enhancing mass in the epidural space on MRI. Differentiating between the two often requires biopsy, though clinical context (fever, inflammatory markers, constitutional symptoms, risk factors) can favor one over the other. The other options are less likely to present as an enhancing epidural mass with these specific symptoms.

Question 5487

Topic: Bone Tumors

When evaluating a shoulder X-ray, how can an osteophyte be radiographically differentiated from an osteochondroma?

. Osteophytes are always larger
. Osteochondromas show continuity of cortex and medulla with the underlying bone
. Osteophytes cause joint space narrowing
. Osteochondromas are exclusively found at joint margins
. Osteophytes are always pedunculated

Correct Answer & Explanation

. Osteochondromas show continuity of cortex and medulla with the underlying bone

Explanation

The key radiographic feature differentiating an osteochondroma from an osteophyte (or other bone lesion) is the continuity of its cortical and medullary bone with the underlying parent bone. Osteophytes are bony outgrowths at joint margins, associated with degenerative changes, and do not necessarily show this medullary continuity. Osteochondromas can be sessile or pedunculated and originate from the bone surface, often near growth plates, not exclusively at joint margins.

Question 5488

Topic: 10. Pathology and Oncology

On an 84-year-old patient's shoulder X-ray, you observe a solitary, well-defined, expansile lytic lesion in the proximal humerus without periosteal reaction. What is the most common benign bone tumor in this age group, and a likely differential for such a lesion (though often asymptomatic)?

. Osteosarcoma
. Enchondroma
. Chondrosarcoma
. Metastatic lesion
. Ewing sarcoma

Correct Answer & Explanation

. Enchondroma

Explanation

A solitary, well-defined lytic lesion in an elderly patient, especially if asymptomatic, could be an enchondroma, which is a common benign cartilage tumor. In the proximal humerus, these are often incidental findings. While metastatic lesions (option D) are more common in the elderly as a general rule for bone lesions, the description 'well-defined, expansile, no periosteal reaction' less fits typical aggressive metastasis, which are often poorly defined, lytic or blastic, with or without periosteal reaction. Osteosarcoma and Ewing sarcoma are aggressive malignant tumors typically seen in younger patients and would have aggressive features. Chondrosarcoma is a malignant cartilage tumor, but often has more aggressive features or calcifications. Given the phrasing of 'most common benign bone tumor... and a likely differential,' enchondroma is the best answer.

Question 5489

Topic: 10. Pathology and Oncology

An 84-year-old female's X-ray reveals multiple, ill-defined, sclerotic lesions (blastic appearance) throughout the proximal humerus and scapula. This radiographic pattern, particularly in an elderly patient, is most suggestive of:

. Multiple myeloma
. Osteochondromatosis
. Metastatic disease (e.g., from prostate, breast)
. Paget's disease
. Enchondromatosis

Correct Answer & Explanation

. Metastatic disease (e.g., from prostate, breast)

Explanation

Multiple, ill-defined sclerotic (blastic) lesions in bone, especially in an elderly patient, are highly characteristic of metastatic disease from primary tumors like prostate cancer (most common blastic mets in men) or breast cancer (can be mixed lytic/blastic in women). Multiple myeloma typically presents with 'punched-out' purely lytic lesions. Osteochondromatosis and enchondromatosis are benign. Paget's disease can cause sclerotic changes, but often with cortical thickening and bone enlargement, usually not diffuse ill-defined lesions.

Question 5490

Topic: 10. Pathology and Oncology

When systematically describing an 84-year-old's shoulder X-ray, using the 'ABC'S' mnemonic (Alignment, Bone, Cartilage, Soft tissues), what does the 'C' (Cartilage) primarily refer to on plain radiographs?

. The presence of cartilage calcifications
. The direct visualization of cartilage thickness
. The inference of cartilage integrity by joint space width
. Cartilage tumors
. Chondral erosions

Correct Answer & Explanation

. The inference of cartilage integrity by joint space width

Explanation

On plain radiographs, cartilage itself is radiolucent and not directly visualized. Its integrity and thickness are inferred by the width of the joint space. Joint space narrowing indicates cartilage loss. While cartilage calcifications (CPPD) and erosions (inflammatory arthritis) can be seen, the primary assessment of 'cartilage' with ABC'S on plain film refers to joint space width.

Question 5491

Topic: 10. Pathology and Oncology

A 10-year-old child presents with a painful L5-S1 spondylolysis. MRI shows no significant slip, but a high signal intensity within the pars defect on T2-weighted images. What does this finding suggest?

. Advanced degenerative changes
. Complete pseudarthrosis
. Active bone edema, indicating acute/subacute pars stress reaction or fracture
. Infection of the pars interarticularis
. Malignant tumor infiltration

Correct Answer & Explanation

. Active bone edema, indicating acute/subacute pars stress reaction or fracture

Explanation

High signal intensity (edema) on T2-weighted MRI within the pars defect of a child or adolescent with spondylolysis indicates an active, acute, or subacute stress reaction or fracture. This finding suggests a higher potential for healing with conservative management (e.g., bracing, activity restriction) compared to a chronic, non-edematous defect.

Question 5492

Topic: 10. Pathology and Oncology

A 12-year-old patient presents with multiple enchondromas of the hands. On examination, several soft, bluish subcutaneous nodules are noted on the digits and forearm. Which of the following is true regarding this patient's syndrome compared to Ollier disease?

. It has a lower risk of malignant transformation.
. It is characterized by the presence of soft tissue hemangiomas.
. It primarily exhibits an autosomal recessive inheritance pattern.
. It strictly affects only one side of the body.
. It is caused by a mutation in the EXT1 gene.

Correct Answer & Explanation

. It is characterized by the presence of soft tissue hemangiomas.

Explanation

The presence of multiple enchondromas combined with soft tissue hemangiomas characterizes Maffucci syndrome. Ollier disease involves multiple enchondromas without hemangiomas. Maffucci syndrome carries a higher risk of malignant transformation (e.g., to chondrosarcoma) than Ollier disease.

Question 5493

Topic: 10. Pathology and Oncology

A 35-year-old woman presents with exquisite, sharp pain in her right index fingertip that is severely exacerbated by cold weather. On examination, there is a faint bluish discoloration beneath the nail plate. Love's pin test and the Hildreth test are positive. What is the most likely diagnosis?

. Enchondroma
. Mucous cyst
. Giant cell tumor of the tendon sheath
. Glomus tumor
. Subungual melanoma

Correct Answer & Explanation

. Glomus tumor

Explanation

A glomus tumor is a benign hamartoma of the glomus body (involved in thermoregulation). The classic triad is severe paroxysmal pain, point tenderness (Love's test), and cold intolerance. Hildreth's test (relief of pain with a tourniquet) is highly specific.

Question 5494

Topic: 10. Pathology and Oncology

A 34-year-old female presents with severe, paroxysmal pain in her right index fingertip. The pain is exacerbated by cold weather. On examination, there is exquisite pinpoint tenderness over the nail bed, and the pain is significantly relieved when a tourniquet is applied to the base of the finger. A faint blue hue is noted beneath the lunula. What is the most likely diagnosis?

. Giant cell tumor of the tendon sheath
. Epidermal inclusion cyst
. Glomus tumor
. Enchondroma
. Mucoid cyst

Correct Answer & Explanation

. Glomus tumor

Explanation

The classic presentation of a glomus tumor includes the triad of hypersensitivity to cold, severe paroxysmal pain, and localized pinpoint tenderness (Love's test). Hildreth's test (relief of pain with tourniquet ischemia) is highly specific. These benign hamartomas arise from the neuromyoarterial glomus bodies, most commonly in the subungual region.

Question 5495

Topic: 10. Pathology and Oncology

A 40-year-old female presents with severe, paroxysmal pain in her ring finger that is exacerbated by cold weather. On examination, there is exquisite point tenderness at the base of the nail bed. The pain completely resolves temporarily when a blood pressure cuff is inflated around her upper arm. What is the most likely diagnosis?

. Enchondroma
. Epidermal inclusion cyst
. Glomus tumor
. Mucous cyst
. Neuroma

Correct Answer & Explanation

. Glomus tumor

Explanation

The patient's clinical presentation is classic for a glomus tumor. The triad of symptoms includes temperature sensitivity (cold intolerance), severe paroxysmal pain, and exquisite point tenderness (Love's pin test). The temporary relief of pain upon inflation of a tourniquet to induce ischemia is known as Hildreth's sign, which is highly specific for a glomus tumor.

Question 5496

Topic: 10. Pathology and Oncology

A 28-year-old mechanic sustains a high-pressure paint injection injury to the volar aspect of his right index finger. He presents to the ER 2 hours later with a small puncture wound, mild swelling, and minimal pain. What is the most appropriate immediate management?

. Local wound care, oral antibiotics, and discharge home with close follow-up
. Bedside incision and drainage under digital block
. Administration of high-dose intravenous corticosteroids to prevent chemical necrosis
. Emergent wide surgical debridement in the operating room
. Application of a warm compress and elevation of the extremity

Correct Answer & Explanation

. Emergent wide surgical debridement in the operating room

Explanation

High-pressure injection injuries to the hand are surgical emergencies, despite often presenting with benign-appearing, small puncture wounds and minimal initial pain. The injected material (paint, grease, oil) travels rapidly along tissue planes, causing severe chemical irritation, tissue necrosis, and compartmental pressure elevation. Emergent, extensive open surgical debridement and irrigation in the operating room are required to prevent severe morbidity, including amputation.

Question 5497

Topic: 10. Pathology and Oncology

A 45-year-old female presents with severe, lancinating pain in her left ring fingertip, exquisitely sensitive to cold temperatures. Examination reveals point tenderness and a faint bluish discoloration beneath the nail bed. What is the most likely diagnosis?

. Enchondroma
. Mucous cyst
. Glomus tumor
. Giant cell tumor of tendon sheath
. Squamous cell carcinoma

Correct Answer & Explanation

. Glomus tumor

Explanation

Glomus tumors are benign, neuromyoarterial hamartomas of the glomus body. They classically present with a distinct clinical triad: pinpoint severe pain, hypersensitivity to cold, and a subungual bluish discoloration.

Question 5498

Topic: 10. Pathology and Oncology

Which histological feature is characteristic of a benign osteochondroma?

. Cartilage cap continuous with the periosteum, with disorganized growth plate-like structure.
. Atypical chondrocytes with pleomorphism and hyperchromatic nuclei.
. Invasion of surrounding soft tissue.
. Lack of a distinct cartilage cap, with disorganized woven bone.
. Predominance of multinucleated giant cells within a fibrous stroma.

Correct Answer & Explanation

. Cartilage cap continuous with the periosteum, with disorganized growth plate-like structure.

Explanation

An osteochondroma is characterized by an osseous projection from the bone surface, capped by hyaline cartilage. Crucially, the cartilage cap of the osteochondroma is continuous with the periosteum, and the underlying trabecular bone of the lesion is continuous with the medullary cavity of the parent bone. The cartilage cap has an organized growth plate-like structure (enchondral ossification), which is benign. Atypical chondrocytes and invasion are signs of malignancy (e.g., chondrosarcoma). Giant cells suggest giant cell tumor. Disorganized woven bone without a cap might be fibrous dysplasia or other benign bone lesions, but not osteochondroma.

Question 5499

Topic: 10. Pathology and Oncology

In bone tumors, what is the significance of a 'Codman triangle' observed on plain radiographs?

. It represents subperiosteal new bone formation due to chronic infection.
. It indicates aggressive, rapidly growing tumor that has lifted the periosteum.
. It is pathognomonic for osteoid osteoma.
. It suggests a benign, slow-growing lesion.
. It is a sign of reactive bone formation around a fibrous lesion.

Correct Answer & Explanation

. It indicates aggressive, rapidly growing tumor that has lifted the periosteum.

Explanation

A Codman triangle (or Codman's triangle) is a triangular area of new bone formation at the angle where the elevated periosteum meets the cortical bone. It indicates that an aggressive lesion (often a malignant tumor like osteosarcoma, but also aggressive infection or trauma) is rapidly growing and lifting the periosteum faster than it can lay down new bone. It is a sign of rapid periosteal elevation, not necessarily pathognomonic but highly suggestive of an aggressive process, typically malignant.

Question 5500

Topic: 10. Pathology and Oncology

A 50-year-old female presents with a slowly growing, painless mass in her posterior thigh that has been present for 6 months. It is firm and measures 5x3 cm. MRI shows a well-defined, heterogeneous mass with signal characteristics suggestive of a soft tissue sarcoma. What is the most appropriate next diagnostic step?

. Incisional biopsy
. Excisional biopsy
. Core needle biopsy
. Fine needle aspiration (FNA)
. PET scan

Correct Answer & Explanation

. Core needle biopsy

Explanation

For a suspected soft tissue sarcoma, a core needle biopsy is the most appropriate next diagnostic step. It provides adequate tissue for histological diagnosis and grading without contaminating a large area of tissue, which is critical for future limb-sparing surgery. The biopsy tract must be carefully planned by or with an experienced musculoskeletal oncologist to ensure it can be completely excised en bloc with the tumor. Incisional or excisional biopsies are generally avoided for suspected sarcomas due to the risk of tumor seeding and complicating definitive surgical margins. FNA often yields insufficient tissue for definitive diagnosis and grading. PET scans are used for staging, not primary diagnosis.

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