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10. Pathology and Oncology MCQs

Practice Set 264 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 5261

Topic: 10. Pathology and Oncology

A 48-year-old patient presents with a lesion in the sternum that is painful. Biopsy confirms a Grade 2 chondrosarcoma. Which of the following is an absolute contraindication for intralesional curettage as definitive treatment?

. Size of the lesion greater than 5 cm
. Patient age over 60 years
. Involvement of a weight-bearing bone
. Histological grade of the tumor (Grade 2 or higher)
. Location in the axial skeleton

Correct Answer & Explanation

. Histological grade of the tumor (Grade 2 or higher)

Explanation

Intralesional curettage is an absolute contraindication for conventional chondrosarcomas of Grade 2 or higher due to the extremely high risk of local recurrence and potential for dedifferentiation. It is only considered in highly selected, low-grade (Grade 1) lesions, often with adjuvant therapies. While size, age, and location can influence management, the histological grade is the most critical factor contraindicating intralesional treatment as a definitive approach.

Question 5262

Topic: 10. Pathology and Oncology

A 30-year-old pregnant patient is diagnosed with a Grade 1 chondrosarcoma of the proximal tibia. What is the most appropriate management approach?

. Immediate wide en bloc resection regardless of pregnancy stage
. Delay surgery until after delivery, with close monitoring
. Start systemic chemotherapy immediately due to pregnancy
. Perform radiation therapy to control tumor growth
. Intralesional curettage to minimize surgical invasiveness

Correct Answer & Explanation

. Immediate wide en bloc resection regardless of pregnancy stage

Explanation

Grade 1 chondrosarcoma, while low-grade, is still a malignant tumor. Surgical wide en bloc resection is the definitive treatment. Delaying surgery for a malignant tumor (even low-grade) until after delivery carries risks of tumor progression and potential dedifferentiation. The risk to the mother from delay generally outweighs the risks of surgery during pregnancy, especially in the second trimester. Chemotherapy and radiation are ineffective. Intralesional curettage is inadequate for chondrosarcoma.

Question 5263

Topic: 10. Pathology and Oncology

Which of the following genes is implicated in the development of both Ollier's disease and Maffucci syndrome, which are associated with an increased risk of chondrosarcoma?

. TP53
. RB1
. IDH1/IDH2
. SMAD4
. EXT1/EXT2

Correct Answer & Explanation

. IDH1/IDH2

Explanation

Somatic mutations in IDH1 and IDH2 genes are highly prevalent in enchondromas and chondrosarcomas, including those associated with Ollier's disease and Maffucci syndrome. These mutations are considered oncogenic drivers in chondrogenesis. EXT1/EXT2 mutations are associated with hereditary multiple exostoses (HME) and secondary peripheral chondrosarcoma, not Ollier's or Maffucci. TP53 and RB1 are tumor suppressor genes involved in various cancers but not specifically linked to these enchondromatoses. SMAD4 is associated with juvenile polyposis syndrome.

Question 5264

Topic: 10. Pathology and Oncology

What is the typical growth pattern of a juxtacortical (periosteal) chondrosarcoma?

. Arises within the medullary cavity and expands outward
. Originates from the synovial membrane of a joint
. Grows on the surface of the bone, beneath the periosteum, with minimal medullary involvement
. A rapidly invasive tumor with early distant metastasis
. Characterized by extensive soft tissue involvement without bone erosion

Correct Answer & Explanation

. Grows on the surface of the bone, beneath the periosteum, with minimal medullary involvement

Explanation

Juxtacortical (or periosteal) chondrosarcoma is a rare variant that typically arises from the surface of the bone, beneath the periosteum, growing outwards while often causing cortical erosion or remodeling but with minimal or no involvement of the medullary cavity. It is a surface lesion, distinct from central chondrosarcoma. The other options describe different types of tumors or growth patterns.

Question 5265

Topic: 10. Pathology and Oncology

A 60-year-old patient presents with chronic hip pain. Imaging reveals a large, lobulated mass within the left acetabulum with characteristic chondroid matrix. Biopsy confirms Grade 2 chondrosarcoma. The orthopedic oncologist determines that complete wide en bloc resection would necessitate a hemipelvectomy due to extensive involvement. What is the most appropriate treatment recommendation?

. Palliative chemotherapy and radiation to reduce tumor burden
. Intralesional curettage to preserve limb function
. External hemipelvectomy for definitive local control
. Internal hemipelvectomy, if possible, with reconstruction
. Observation with pain management

Correct Answer & Explanation

. Internal hemipelvectomy, if possible, with reconstruction

Explanation

For a large, resectable Grade 2 chondrosarcoma of the acetabulum requiring a hemipelvectomy for wide margins, an internal hemipelvectomy with reconstruction (e.g., custom prosthesis, allograft, or arthrodesis) is generally preferred over external hemipelvectomy (amputation) if functional limb salvage is oncologically feasible. While a true 'wide en bloc' might be very difficult to achieve, the goal is still wide margins, and sacrificing the limb is a last resort. Palliative chemo/radiation is not primary curative. Intralesional curettage is inadequate. Observation is inappropriate for a Grade 2 tumor.

Question 5266

Topic: 10. Pathology and Oncology

Which of the following is a key distinguishing feature of mesenchymal chondrosarcoma from conventional chondrosarcoma?

. Predominantly affects the elderly population
. Characterized by a biphasic histology of small round cells and areas of mature cartilage
. Known for its high resistance to chemotherapy and radiation
. Almost exclusively found in the appendicular skeleton
. Low metastatic potential

Correct Answer & Explanation

. Characterized by a biphasic histology of small round cells and areas of mature cartilage

Explanation

Mesenchymal chondrosarcoma is characterized by a distinctive biphasic histology, featuring primitive small round to spindle cells (often with a hemangiopericytoma-like vascular pattern) admixed with islands of well-differentiated hyaline cartilage. It typically affects younger patients, is more responsive to chemotherapy than conventional chondrosarcoma, can occur in axial and craniofacial sites, and has a relatively high metastatic potential. Conventional chondrosarcoma lacks the small round cell component and is largely resistant to chemotherapy.

Question 5267

Topic: 10. Pathology and Oncology

When evaluating a patient for potential chondrosarcoma, elevated serum alkaline phosphatase (ALP) might suggest what?

. Liver metastasis
. Bone metastasis or aggressive bone turnover
. Renal dysfunction
. A benign bone lesion
. No clinical significance in this context

Correct Answer & Explanation

. Bone metastasis or aggressive bone turnover

Explanation

Elevated serum alkaline phosphatase (ALP) can indicate increased osteoblastic activity, which may be associated with bone formation and turnover, commonly seen in aggressive bone tumors, healing fractures, or bone metastases. Therefore, in the context of chondrosarcoma, it might suggest a more aggressive tumor, extensive bone involvement, or potential bone metastasis. It's not specific to chondrosarcoma or malignancy, but it flags increased osteoblastic activity. Liver metastases could elevate ALP but would typically be accompanied by elevated liver-specific enzymes.

Question 5268

Topic: 10. Pathology and Oncology

A 20-year-old female presents with a painful lesion in the proximal tibia. Radiographs show a lytic lesion in the epiphysis. Biopsy reveals uniform, polygonal cells with clear cytoplasm and occasional multinucleated giant cells. Which genetic mutation is most commonly associated with this specific type of chondrosarcoma?

. IDH1/IDH2
. H3F3B
. TP53
. BRAF
. EXT1/EXT2

Correct Answer & Explanation

. H3F3B

Explanation

Clear cell chondrosarcoma, as described, is commonly associated with H3F3B mutations. IDH1/IDH2 mutations are more typical of conventional central chondrosarcoma and enchondroma. TP53 is a general tumor suppressor. BRAF is associated with melanoma and some other cancers. EXT1/EXT2 are related to osteochondromas and secondary peripheral chondrosarcomas.

Question 5269

Topic: 10. Pathology and Oncology

What is the primary role of intraoperative frozen section analysis during chondrosarcoma surgery?

. To confirm the diagnosis of chondrosarcoma
. To determine the histological grade of the tumor
. To assess the adequacy of surgical margins
. To identify distant metastatic disease
. To differentiate between primary and secondary chondrosarcoma

Correct Answer & Explanation

. To assess the adequacy of surgical margins

Explanation

Intraoperative frozen section analysis is primarily used to assess the adequacy of surgical margins during tumor resection. This helps the surgeon determine if additional tissue needs to be removed to achieve clear margins before closing the wound. While it can sometimes confirm diagnosis or grade, its most crucial role during surgery is margin assessment. Distant metastases are evaluated by preoperative imaging. Differentiating primary/secondary is usually done by history and full histopathology.

Question 5270

Topic: Bone Tumors

Which of the following scenarios would most likely warrant consideration of neoadjuvant therapy (chemotherapy or radiation) for a chondrosarcoma, despite its general resistance?

. Grade 1 conventional chondrosarcoma in the proximal femur
. Small, resectable clear cell chondrosarcoma
. Mesenchymal chondrosarcoma in the spine causing neurological deficit
. Secondary peripheral chondrosarcoma of the scapula
. Low-grade central chondrosarcoma of the phalanx

Correct Answer & Explanation

. Mesenchymal chondrosarcoma in the spine causing neurological deficit

Explanation

While conventional chondrosarcomas are largely resistant, mesenchymal chondrosarcoma is an exception, showing some chemosensitivity. For a mesenchymal chondrosarcoma, especially in a difficult anatomical location like the spine causing neurological deficits, neoadjuvant chemotherapy may be considered to attempt tumor shrinkage and facilitate a safer, more complete resection. For other types of chondrosarcoma, neoadjuvant therapy is generally ineffective and not indicated as primary treatment. Grade 1 or clear cell types are generally managed surgically without neoadjuvant therapy. Peripheral chondrosarcoma is also primarily surgical.

Question 5271

Topic: 10. Pathology and Oncology

When performing an en bloc resection of a chondrosarcoma, what is the 'surgical bed' most prone to contamination if intralesional violation occurs?

. The skin incision
. The neurovascular bundle adjacent to the tumor
. The joint capsule
. The entire wound created by the resection, including soft tissues and bone
. The distant metastatic sites

Correct Answer & Explanation

. The entire wound created by the resection, including soft tissues and bone

Explanation

If intralesional violation (e.g., tumor breach or spillage) occurs during en bloc resection of a chondrosarcoma, the entire surgical wound, including all surrounding soft tissues and bone that come into contact with tumor cells, becomes potentially contaminated. This significantly increases the risk of local recurrence and necessitates a wider, more radical resection or adjuvant therapy to the entire contaminated field. The goal of en bloc resection is to remove the tumor in one piece, completely encapsulated by normal tissue, without breaching its pseudocapsule.

Question 5272

Topic: Bone Tumors

Which chondrosarcoma variant has a predilection for the craniofacial bones, particularly the maxilla and mandible, and exhibits a high local recurrence rate?

. Clear cell chondrosarcoma
. Dedifferentiated chondrosarcoma
. Mesenchymal chondrosarcoma
. Juxtacortical chondrosarcoma
. Conventional central chondrosarcoma

Correct Answer & Explanation

. Mesenchymal chondrosarcoma

Explanation

Mesenchymal chondrosarcoma has a distinct predilection for axial sites, including the craniofacial bones (especially maxilla, mandible, skull base), spine, and ribs. It is known for its aggressive nature, high local recurrence rate, and metastatic potential. The other types are less common in these specific locations or have different characteristic patterns.

Question 5273

Topic: 10. Pathology and Oncology

A 55-year-old male presents with persistent knee pain. MRI shows a lobulated intramedullary lesion in the distal femur with peripheral enhancement and internal non-enhancing foci. The lesion abuts the physis. Which of the following is the most critical factor to consider when planning a biopsy?

. The patient's age and overall health
. Minimizing trauma to adjacent soft tissues
. Avoiding tumor cell seeding along the biopsy tract
. The type of anesthesia to be used
. Presence of pre-existing hardware

Correct Answer & Explanation

. Avoiding tumor cell seeding along the biopsy tract

Explanation

Avoiding tumor cell seeding along the biopsy tract is paramount for any suspected malignant bone tumor, including chondrosarcoma. The biopsy tract must be planned so that it can be completely resected en bloc with the definitive tumor excision, thus preventing local recurrence from seeded cells. This is a critical principle of oncologic surgery. While other factors are important, preventing seeding is specific to malignant tumor biopsies.

Question 5274

Topic: 10. Pathology and Oncology

A patient with Maffucci syndrome (multiple enchondromatosis and soft tissue hemangiomas) has a significantly increased lifetime risk of developing which type of malignancy?

. Osteosarcoma
. Ewing sarcoma
. Chondrosarcoma
. Fibrosarcoma
. Liposarcoma

Correct Answer & Explanation

. Chondrosarcoma

Explanation

Both Ollier's disease and Maffucci syndrome are associated with a significantly increased lifetime risk of developing secondary conventional central chondrosarcoma, arising from malignant transformation of one of the multiple enchondromas. While other malignancies are possible, chondrosarcoma is the most common and characteristic malignant complication. The risk is generally higher in Maffucci syndrome than in Ollier's disease.

Question 5275

Topic: Bone Tumors

Which type of chondrosarcoma is least likely to respond to systemic chemotherapy?

. Mesenchymal chondrosarcoma
. Dedifferentiated chondrosarcoma (high-grade component)
. Conventional central chondrosarcoma Grade 1
. Conventional central chondrosarcoma Grade 3
. Clear cell chondrosarcoma

Correct Answer & Explanation

. Conventional central chondrosarcoma Grade 1

Explanation

Conventional central chondrosarcoma, particularly Grade 1, is notoriously resistant to systemic chemotherapy. Chemotherapy is generally not indicated for low-grade conventional chondrosarcomas. Mesenchymal chondrosarcoma and the high-grade component of dedifferentiated chondrosarcoma may show some limited response to chemotherapy, but conventional chondrosarcoma overall has poor chemosensitivity, and this is especially true for Grade 1. Clear cell is also largely chemorefractory.

Question 5276

Topic: Bone Tumors

Which statement regarding dedifferentiated chondrosarcoma is correct?

. It represents a progression from Grade 1 to Grade 3 conventional chondrosarcoma.
. It typically arises de novo without a pre-existing cartilaginous lesion.
. It is characterized by a biphasic morphology of low-grade chondrosarcoma and high-grade non-cartilaginous sarcoma.
. It has a better prognosis than conventional Grade 3 chondrosarcoma.
. It is treated effectively with intralesional curettage and radiation.

Correct Answer & Explanation

. It is characterized by a biphasic morphology of low-grade chondrosarcoma and high-grade non-cartilaginous sarcoma.

Explanation

Dedifferentiated chondrosarcoma is pathologically defined by its biphasic morphology, consisting of a low-grade conventional chondrosarcoma component sharply juxtaposed with a high-grade, non-cartilaginous sarcoma (e.g., osteosarcoma, fibrosarcoma). It has a very poor prognosis, worse than conventional Grade 3 chondrosarcoma. It does not simply represent a grade progression but a distinct, more aggressive entity. It often arises from a pre-existing cartilaginous lesion or conventional chondrosarcoma. Intralesional curettage and radiation are ineffective.

Question 5277

Topic: 10. Pathology and Oncology

A 40-year-old male with a history of a resected Grade 1 chondrosarcoma of the proximal humerus develops a rapidly growing, painful soft tissue mass near the previous surgical site. Biopsy shows a high-grade undifferentiated pleomorphic sarcoma. This most likely represents what?

. Local recurrence of Grade 1 chondrosarcoma
. Post-traumatic fibroma
. Dedifferentiated chondrosarcoma
. Metastatic carcinoma
. Benign reactive process

Correct Answer & Explanation

. Dedifferentiated chondrosarcoma

Explanation

The scenario describes a recurrence of a low-grade chondrosarcoma that has transformed into a high-grade, non-cartilaginous sarcoma (undifferentiated pleomorphic sarcoma, UPS). This is the classic presentation of dedifferentiated chondrosarcoma. It's not a simple recurrence of Grade 1, which would retain its low-grade cartilaginous features. The transformation to a high-grade non-cartilaginous component is key. It's highly unlikely to be benign or metastatic carcinoma given the history and location.

Question 5278

Topic: 10. Pathology and Oncology

What is the primary distinguishing feature of a benign osteochondroma from a secondary peripheral chondrosarcoma?

. Presence of a cartilage cap
. Lobulated contour of the lesion
. Thickness of the cartilaginous cap (>1-2 cm in adults)
. Location in the appendicular skeleton
. Pain with activity

Correct Answer & Explanation

. Thickness of the cartilaginous cap (>1-2 cm in adults)

Explanation

The most reliable radiographic and pathological distinguishing feature between a benign osteochondroma and a secondary peripheral chondrosarcoma is the thickness of the cartilaginous cap. In adults, a cap thickness exceeding 1-2 cm (often 2 cm is used as a cutoff) is highly suspicious for malignant transformation. While pain, lobulated contour, and location can be seen in both, cap thickness is the most specific indicator of malignancy in this context.

Question 5279

Topic: 10. Pathology and Oncology

Which staging system is most commonly used for chondrosarcoma?

. TNM (AJCC) Staging System
. Enneking Staging System
. Duke's Staging System
. Ann Arbor Staging System
. Lugano Classification

Correct Answer & Explanation

. TNM (AJCC) Staging System

Explanation

The TNM (Tumor, Node, Metastasis) staging system, developed by the AJCC (American Joint Committee on Cancer), is the most commonly used staging system for bone sarcomas, including chondrosarcoma. The Enneking Staging System (MSTS Staging System) is also widely used for musculoskeletal tumors, focusing on surgical planning based on local aggressiveness. Duke's is for colorectal cancer. Ann Arbor and Lugano are for lymphoma.

Question 5280

Topic: Bone Tumors

A 62-year-old patient undergoes an unplanned intralesional excision for what was thought to be an enchondroma of the proximal femur. Final pathology reveals a Grade 2 chondrosarcoma with positive margins. What is the most appropriate next step?

. Observation with serial imaging
. Adjuvant radiation therapy alone
. Systemic chemotherapy
. Re-excision with wide margins
. Palliative care

Correct Answer & Explanation

. Re-excision with wide margins

Explanation

An unplanned intralesional excision of a Grade 2 chondrosarcoma with positive margins necessitates a planned re-excision with wide margins. This is crucial for local control and to prevent recurrence and potential dedifferentiation. Observation is inadequate. Adjuvant radiation is generally ineffective for conventional chondrosarcoma. Chemotherapy is not a primary treatment for conventional chondrosarcoma. Palliative care is not appropriate given the potential for cure with adequate surgery.

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