Menu

10. Pathology and Oncology MCQs

Practice Set 112 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 2221

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with a permeative lytic lesion in the femoral diaphysis with aggressive periosteal reaction ('onion skinning'). Biopsy reveals uniform small round blue cells. Cytogenetic analysis of this tumor will most likely demonstrate which of the following translocations?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical and radiographic description is classic for Ewing sarcoma. The characteristic cytogenetic abnormality is a balanced translocation t(11;22)(q24;q12), which fuses the EWS gene on chromosome 22 with the FLI1 gene on chromosome 11. This is seen in approximately 85-90% of Ewing sarcomas. t(9;22) is the Philadelphia chromosome (CML), t(X;18) is seen in synovial sarcoma, t(2;13) in alveolar rhabdomyosarcoma, and t(12;16) in myxoid liposarcoma.

Question 2222

Topic: 10. Pathology and Oncology

A 55-year-old patient presents with a slowly enlarging, painful mass in the proximal humerus.

Biopsy reveals a hyaline cartilage matrix with cellular atypia, confirming a diagnosis of central conventional chondrosarcoma. Which of the following genetic mutations is most frequently identified in this specific tumor?

. EXT1 / EXT2
. IDH1 / IDH2
. GNAS
. TP53 / RB1
. RUNX2

Correct Answer & Explanation

. IDH1 / IDH2

Explanation

Mutations in the isocitrate dehydrogenase genes, IDH1 and IDH2, are found in up to 50-60% of central conventional chondrosarcomas and enchondromas. EXT1 and EXT2 mutations are characteristic of multiple hereditary exostoses (osteochondromas). GNAS mutations are seen in fibrous dysplasia. TP53 and RB1 mutations are hallmark aberrations in osteosarcoma.

Question 2223

Topic: 10. Pathology and Oncology

A 15-year-old male presents with deep knee pain awakening him at night. Radiographs show a permeative destructive lesion in the distal femoral metaphysis with a 'sunburst' periosteal reaction and Codman's triangle.

Biopsy confirms high-grade conventional osteosarcoma. What is the most critical prognostic factor for long-term overall survival in this patient?

. Tumor volume at initial presentation
. Histologic subtype (e.g., osteoblastic vs. chondroblastic)
. Presence of skip metastases on initial MRI
. Percentage of tumor necrosis following neoadjuvant chemotherapy
. Patient age and gender at diagnosis

Correct Answer & Explanation

. Percentage of tumor necrosis following neoadjuvant chemotherapy

Explanation

For localized high-grade osteosarcoma, the most important prognostic indicator is the histologic response to neoadjuvant chemotherapy. This is evaluated during the definitive resection. A 'good response' is typically defined as greater than 90% or 99% tumor necrosis. Patients who achieve this level of necrosis have a significantly improved disease-free and overall survival rate compared to 'poor responders' who have extensive viable tumor cells remaining.

Question 2224

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a painful mass in his distal femur. Radiographs display a "sunburst" periosteal reaction and Codman's triangle. Core needle biopsy confirms high-grade intramedullary osteosarcoma. Following a standard protocol of multi-agent neoadjuvant chemotherapy and wide surgical resection, what is the single most important prognostic factor for this patient's long-term survival?

. Initial tumor volume exceeding 200 cubic centimeters
. The specific histologic subtype of the tumor (e.g., chondroblastic vs. telangiectatic)
. The percentage of tumor necrosis observed in the resected specimen
. Presence of a t(11;22) chromosomal translocation
. Patient age at the time of diagnosis

Correct Answer & Explanation

. The percentage of tumor necrosis observed in the resected specimen

Explanation

In patients with localized, high-grade osteosarcoma, the histologic response to neoadjuvant chemotherapy is the single most reliable prognostic factor for long-term survival. A 'good responder' is typically defined as having greater than 90% tumor necrosis in the final resected specimen, which correlates with significantly higher overall survival rates.

Question 2225

Topic: 10. Pathology and Oncology

A 15-year-old male presents with worsening pain in his distal femur. Radiographs reveal a destructive metaphyseal lesion with a 'sunburst' periosteal reaction and Codman's triangle.

Which of the following is the most significant prognostic factor for overall survival in this patient?

. Histologic subtype
. Size of the initial tumor
. Percentage of tumor necrosis following neoadjuvant chemotherapy
. Alkaline phosphatase levels
. Location of the tumor

Correct Answer & Explanation

. Percentage of tumor necrosis following neoadjuvant chemotherapy

Explanation

This patient has an osteosarcoma. The single most important prognostic factor for overall survival in osteosarcoma is the histological response (percentage of tumor necrosis) to neoadjuvant chemotherapy, with >90% necrosis indicating a good response.

Question 2226

Topic: 10. Pathology and Oncology

An 11-year-old boy presents with a diaphyseal tumor of the femur. Radiographs show an 'onion-skin' periosteal reaction. A biopsy reveals small, round blue cells. Which of the following cytogenetic abnormalities is most pathognomonic for this tumor?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma classically presents in the diaphysis of long bones with an 'onion-skin' appearance. It is characterized by small, round blue cells and is most commonly associated with the t(11;22)(q24;q12) chromosomal translocation, resulting in the EWS-FLI1 fusion protein.

Question 2227

Topic: 10. Pathology and Oncology

A 14-year-old female presents with pain in her proximal humerus. Radiographs show an eccentric, expansile, lytic lesion with thin cortices. MRI demonstrates fluid-fluid levels. A biopsy confirms an aneurysmal bone cyst (ABC). What is the genetic translocation most commonly associated with primary ABCs?

. t(11;22) (q24;q12)
. t(16;17) (q22;p13)
. t(X;18) (p11;q11)
. t(12;16) (q13;p11)
. t(2;13) (q35;q14)

Correct Answer & Explanation

. t(16;17) (q22;p13)

Explanation

Primary aneurysmal bone cysts are neoplasms characterized by a rearrangement of the USP6 gene on chromosome 17p13. The most common translocation is t(16;17)(q22;p13) which fuses the promoter region of CDH11 to USP6.

Question 2228

Topic: 10. Pathology and Oncology

A 24-year-old male presents with a slowly growing, painful mass in the anterior compartment of his left leg. Radiographs show an eccentric, multi-loculated, 'soap-bubble' osteolytic lesion in the diaphysis of the tibia. A biopsy is performed. Histological analysis reveals nests of epithelial-appearing cells in a fibrous stroma. Immunohistochemistry is strongly positive for cytokeratin. What is the most likely diagnosis?

. Osteofibrous dysplasia
. Ewing sarcoma
. Adamantinoma
. Chondromyxoid fibroma
. Synovial sarcoma

Correct Answer & Explanation

. Adamantinoma

Explanation

Adamantinoma is a rare, low-grade malignant bone tumor that almost exclusively occurs in the diaphysis of the tibia. Radiographically, it appears as a multi-loculated 'soap-bubble' lesion. Histologically, it is biphasic with both epithelial cells and osteofibrous stroma. The definitive diagnostic marker is its strong immunohistochemical positivity for cytokeratins. Osteofibrous dysplasia occurs in the same location and demographic but lacks the cytokeratin-positive epithelial cells and is a benign lesion.

Question 2229

Topic: 10. Pathology and Oncology

An 18-year-old male presents with knee pain. A biopsy of a distal femoral lesion is performed. Histology is shown.

The definitive diagnosis of osteosarcoma requires the presence of which of the following histologic features?

. Chondroid matrix production
. Small blue round cells with CD99 positivity
. Malignant cells directly producing osteoid
. Spindle cells arranged in a herringbone pattern
. Multinucleated giant cells in a background of mononuclear cells

Correct Answer & Explanation

. Malignant cells directly producing osteoid

Explanation

The defining histologic characteristic of osteosarcoma is the production of osteoid directly by malignant mesenchymal cells. While cartilage or fibrous tissue may be present (in chondroblastic or fibroblastic variants), malignant osteoid must be identified for the diagnosis. Small blue round cells correspond to Ewing sarcoma, a herringbone pattern corresponds to fibrosarcoma, and giant cells suggest giant cell tumor of bone.

Question 2230

Topic: 10. Pathology and Oncology
A 45-year-old male presents with a dull ache in his proximal humerus. Radiographs reveal a 6-cm intramedullary lytic lesion with rings and arcs of calcification. MRI demonstrates endosteal scalloping involving 75% of the cortical thickness. Biopsy confirms a grade II chondrosarcoma. Which of the following is the most appropriate surgical management?
. Intralesional curettage, phenol adjuvant, and bone grafting
. Wide local excision with margins
. Neoadjuvant chemotherapy followed by wide local excision
. Radiation therapy followed by intralesional excision
. Observation with serial radiographs every 6 months

Correct Answer & Explanation

. Wide local excision with margins

Explanation

This patient has a Grade II (intermediate grade) chondrosarcoma of the proximal humerus. Chondrosarcomas are largely resistant to traditional chemotherapy and radiation therapy. High-grade (Grade II and III) chondrosarcomas, as well as those in the pelvis or proximal appendicular skeleton, require wide local excision with negative margins to minimize local recurrence. Intralesional curettage is reserved for benign enchondromas or selected Grade I (low-grade) chondrosarcomas in the appendicular skeleton.

Question 2231

Topic: 10. Pathology and Oncology
A 15-year-old male undergoes wide resection of a conventional high-grade osteosarcoma of the distal femur after completing 10 weeks of neoadjuvant chemotherapy (methotrexate, doxorubicin, and cisplatin). Pathological analysis of the resected specimen is evaluated using the Huvos grading system. What percentage of tumor necrosis is required to be classified as a 'good response' (Grade III or IV), which correlates with a significantly better prognosis?
. Greater than 50%
. Greater than 75%
. Greater than 90%
. Greater than 95%
. 100% necrosis only

Correct Answer & Explanation

. Greater than 90%

Explanation

The histologic response to neoadjuvant chemotherapy is one of the most important prognostic factors for patients with osteosarcoma. The Huvos grading system categorizes response based on the percentage of tumor necrosis. A 'good response', defined as Huvos Grade III (>90% but <100% necrosis) or Grade IV (100% necrosis), is strongly correlated with improved long-term disease-free and overall survival. Anything less than 90% necrosis is considered a poor response.

Question 2232

Topic: 10. Pathology and Oncology
A 16-year-old male undergoes wide surgical resection for a conventional high-grade osteosarcoma of the distal femur after completing 10 weeks of neoadjuvant multi-agent chemotherapy. Histologic analysis of the resected specimen is performed. Which of the following findings is the most significant independent predictor of long-term survival?
. Surgical margins > 5 cm
. Presence of a skip metastasis
. > 90% tumor necrosis in the resection specimen
. Predominance of chondroblastic subtype
. High levels of alkaline phosphatase post-resection

Correct Answer & Explanation

. > 90% tumor necrosis in the resection specimen

Explanation

In high-grade non-metastatic osteosarcoma, the histologic response to neoadjuvant chemotherapy (percentage of tumor necrosis) is the single most important prognostic factor. A 'good responder' is typically defined as having ≥90% tumor necrosis in the resected specimen, which correlates with significantly improved disease-free and overall survival.

Question 2233

Topic: 10. Pathology and Oncology

A 12-year-old female presents with pain and swelling in her mid-thigh. Radiographs reveal a permeative, destructive diaphyseal lesion with an "onion-skin" periosteal reaction. Biopsy demonstrates small, round, blue cells. Which of the following cytogenetic abnormalities is most characteristically associated with this tumor?

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

Correct Answer & Explanation

. t(11;22)

Explanation

The clinical and radiographic presentation describes Ewing sarcoma. The hallmark cytogenetic abnormality of Ewing sarcoma is a balanced translocation between chromosomes 11 and 22, t(11;22)(q24;q12), which results in the fusion of the EWS gene with the FLI1 gene. The tumor cells strongly express CD99 on immunohistochemistry.

Question 2234

Topic: 10. Pathology and Oncology

A 14-year-old male presents with worsening night pain in his distal femur.

The radiograph shows a mixed lytic/sclerotic lesion with a 'sunburst' periosteal reaction and Codman's triangle. A biopsy confirms conventional osteosarcoma. Which of the following genetic alterations is most classically associated with the pathogenesis of this tumor?

. t(11;22) translocation
. Mutations in the p53 and Rb tumor suppressor genes
. t(X;18) translocation
. Amplification of the c-myc oncogene
. t(2;13) translocation

Correct Answer & Explanation

. Mutations in the p53 and Rb tumor suppressor genes

Explanation

Conventional osteosarcoma is highly associated with mutations in the p53 (associated with Li-Fraumeni syndrome) and Rb (retinoblastoma) tumor suppressor genes. Option A (t(11;22)) is characteristic of Ewing sarcoma (EWS-FLI1 fusion). Option C (t(X;18)) is seen in Synovial Sarcoma (SYT-SSX). Option E (t(2;13)) is associated with Alveolar Rhabdomyosarcoma (PAX3-FOXO1).

Question 2235

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with a destructive, bone-forming lesion in the distal femoral metaphysis with a 'sunburst' periosteal reaction. Biopsy confirms high-grade osteosarcoma. Assuming the patient has localized disease, which of the following is the most important prognostic factor for long-term survival?

. Patient age at presentation
. Histologic subtype (e.g., osteoblastic vs. chondroblastic)
. Extent of tumor necrosis following neoadjuvant chemotherapy
. Size of the primary tumor
. Serum alkaline phosphatase level at presentation

Correct Answer & Explanation

. Extent of tumor necrosis following neoadjuvant chemotherapy

Explanation

In non-metastatic high-grade osteosarcoma, the histologic response to neoadjuvant chemotherapy (typically measured by the percentage of tumor necrosis) is one of the most powerful prognostic indicators. Greater than 90% necrosis indicates a 'good responder' and is associated with significantly higher overall survival.

Question 2236

Topic: 10. Pathology and Oncology

A 55-year-old man presents with dull, aching pain in his right pelvis for 6 months. Radiographs reveal a large, lytic lesion in the right ilium with 'popcorn' calcifications.

Biopsy demonstrates a moderately cellular cartilage tumor with plump, binucleated chondrocytes. What is the most appropriate definitive management for this patient?

. Neoadjuvant chemotherapy followed by wide surgical resection
. Wide surgical resection alone
. Intralesional curettage and bone grafting
. Primary radiation therapy
. Observation with serial radiographs

Correct Answer & Explanation

. Wide surgical resection alone

Explanation

Conventional chondrosarcoma is generally resistant to both chemotherapy and radiation therapy due to its poor vascularity and slow growth. The mainstay of treatment for intermediate or high-grade chondrosarcoma of the pelvis is wide surgical resection.

Question 2237

Topic: 10. Pathology and Oncology

A 15-year-old boy is diagnosed with a high-grade intramedullary osteosarcoma of the distal femur.

He undergoes a standard protocol of neoadjuvant chemotherapy followed by wide surgical resection. Which of the following factors has been established as the single most important prognostic indicator for his long-term survival?

. Tumor volume at initial presentation
. Histologic subtype of the tumor
. Percentage of tumor necrosis following neoadjuvant chemotherapy
. Anatomic location of the lesion
. Presence of a pathological fracture at presentation

Correct Answer & Explanation

. Percentage of tumor necrosis following neoadjuvant chemotherapy

Explanation

The most important prognostic factor for survival in patients with localized, high-grade osteosarcoma is the histologic response of the tumor to neoadjuvant chemotherapy. Patients with >90% tumor necrosis are considered 'good responders' and have a significantly better prognosis and 5-year survival rate compared to 'poor responders' (<90% necrosis).

Question 2238

Topic: 10. Pathology and Oncology
A 60-year-old man presents with progressive, deep pelvic pain. A core needle biopsy of a large lytic lesion in the ilium confirms the diagnosis of conventional Grade II chondrosarcoma. Staging studies are negative for metastasis. Which of the following is the standard of care for definitive management?
. Neoadjuvant chemotherapy followed by wide surgical excision
. Wide surgical excision alone
. Intralesional curettage with adjuvant cryotherapy and cementation
. Primary fractionated radiation therapy
. Surgical excision followed by adjuvant systemic chemotherapy

Correct Answer & Explanation

. Wide surgical excision alone

Explanation

Conventional chondrosarcoma is notoriously resistant to both systemic chemotherapy and radiation therapy due to its poor vascularity and slow division rate. The mainstay of treatment for intermediate and high-grade (Grade II and III) chondrosarcomas, as well as those located in the pelvis, is wide surgical excision with negative margins. Intralesional curettage is only appropriate for some low-grade (Grade I) lesions in the appendicular skeleton.

Question 2239

Topic: Bone Tumors

A 65-year-old male presents with deep bone pain, fatigue, and recent weight loss.

Radiographs demonstrate multiple 'punched-out' lytic lesions in his skull, pelvis, and proximal femurs. Based on the most likely diagnosis, which of the following laboratory findings is expected?

. Monoclonal spike on serum protein electrophoresis (SPEP)
. Elevated serum alkaline phosphatase with normal serum calcium
. Translocation t(11;22)
. Presence of the BCR-ABL fusion gene
. Mutation in the GNAS1 gene

Correct Answer & Explanation

. Monoclonal spike on serum protein electrophoresis (SPEP)

Explanation

The clinical presentation and 'punched-out' lytic lesions are classic for Multiple Myeloma, the most common primary malignancy of bone in adults. Diagnosis is supported by identifying a monoclonal spike (M-protein) on serum protein electrophoresis (SPEP) or urine protein electrophoresis (UPEP, Bence Jones proteins).

Question 2240

Topic: 10. Pathology and Oncology
A 60-year-old male presents with a dull, aching pain in his proximal thigh. Radiographs reveal a large, destructive lytic lesion in the proximal femur with intralesional 'popcorn' calcifications. Core needle biopsy confirms a conventional, intermediate-grade (Grade II) chondrosarcoma. What is the standard, definitive treatment for this primary bone tumor?
. Neoadjuvant chemotherapy followed by wide surgical resection
. Wide surgical resection alone
. Intralesional curettage supplemented with liquid nitrogen cryotherapy
. Primary fractionated external beam radiation therapy
. Radiofrequency ablation combined with cementation

Correct Answer & Explanation

. Wide surgical resection alone

Explanation

Conventional chondrosarcomas are notoriously resistant to both chemotherapy and radiation therapy due to their low mitotic rate and poor vascularity within the hyaline cartilage matrix. Therefore, the standard of care for Grade II and III conventional chondrosarcomas is wide surgical resection alone.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page