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10. Pathology and Oncology MCQs

Practice Set 113 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 2241

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with progressive knee pain and swelling for two months. Radiographs demonstrate a metaphyseal lesion in the distal femur with a 'sunburst' periosteal reaction and Codman's triangle. A biopsy confirms a high-grade primary bone sarcoma. Which of the following genetic alterations is most closely associated with this condition?

. t(11;22) translocation
. Mutation of the EXT1 gene
. Inactivation of the RB1 and TP53 tumor suppressor genes
. t(X;18) translocation
. GNAS1 mutation

Correct Answer & Explanation

. Inactivation of the RB1 and TP53 tumor suppressor genes

Explanation

The clinical presentation and imaging are classic for osteosarcoma. Osteosarcoma is strongly associated with mutations or inactivations of tumor suppressor genes, particularly RB1 (Retinoblastoma gene) and TP53 (Li-Fraumeni syndrome). t(11;22) is seen in Ewing sarcoma. t(X;18) is seen in synovial sarcoma. EXT1 is associated with multiple hereditary exostoses. GNAS1 is associated with fibrous dysplasia.

Question 2242

Topic: 10. Pathology and Oncology

A 14-year-old girl presents with pain and swelling over her distal femur. Radiographs show an eccentric, expansile, lytic lesion in the metaphysis. MRI demonstrates multiple fluid-fluid levels. A biopsy confirms an aneurysmal bone cyst (ABC).

What is the classic genetic translocation associated with primary ABCs?

. t(11;22)
. t(12;16)
. t(16;17)
. t(X;18)
. t(9;22)

Correct Answer & Explanation

. t(16;17)

Explanation

Primary Aneurysmal Bone Cysts (ABCs) are neoplastic processes often associated with a characteristic genetic translocation, t(16;17)(q22;p13), which results in the fusion of the CDH11 and USP6 genes. Secondary ABCs can occur in association with other tumors (like giant cell tumors or chondroblastoma) but lack this specific translocation. t(11;22) is associated with Ewing sarcoma; t(12;16) with myxoid liposarcoma; t(X;18) with synovial sarcoma.

Question 2243

Topic: Bone Tumors

A 65-year-old male presents with severe, atraumatic mid-back pain. Radiographs reveal a compression fracture of T8. Laboratory workup shows anemia, hypercalcemia, and an elevated creatinine. Serum protein electrophoresis demonstrates a monoclonal spike. Which of the following is the most sensitive and appropriate imaging modality to detect additional osteolytic bone lesions in this patient?

. Technetium-99m whole-body bone scan
. Whole-body MRI or Low-dose whole-body CT
. Ultrasound
. Dual-energy X-ray absorptiometry (DEXA)
. Gallium-67 scan

Correct Answer & Explanation

. Whole-body MRI or Low-dose whole-body CT

Explanation

Multiple myeloma lesions are purely lytic and typically do not provoke an osteoblastic response, making traditional Technetium-99m bone scans highly unreliable (high false-negative rate). Whole-body MRI and low-dose whole-body CT (or PET-CT) are much more sensitive for detecting lytic myeloma bone disease and are the current standard of care.

Question 2244

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with progressive distal femur pain. Imaging and subsequent biopsy confirm conventional high-grade osteosarcoma.

Following neoadjuvant chemotherapy, the tumor is resected. Which of the following histologic findings in the resection specimen is the most critical prognostic indicator of overall survival?

. Presence of MDM2 amplification
. Degree of tumor necrosis less than 90%
. Predominance of chondroblastic over osteoblastic matrix
. Intralesional hemorrhage and cystic changes
. Identification of multinucleated giant cells

Correct Answer & Explanation

. Degree of tumor necrosis less than 90%

Explanation

The most important prognostic factor for conventional high-grade osteosarcoma following neoadjuvant chemotherapy is the histologic response to the chemotherapy. A good response is defined as greater than 90% tumor necrosis in the resection specimen. Less than 90% tumor necrosis (a poor response) is associated with lower overall survival and a higher risk of systemic metastasis.

Question 2245

Topic: 10. Pathology and Oncology
A 50-year-old male presents with a large, expansile lesion in the proximal femur showing endosteal scalloping and 'popcorn' calcifications on radiographs. Biopsy confirms a grade II chondrosarcoma. What is the most appropriate definitive management?
. Neoadjuvant chemotherapy followed by wide surgical excision
. Wide surgical excision alone
. Intralesional curettage, adjuvant phenol, and cementation
. Primary external beam radiation therapy
. Denosumab therapy followed by resection

Correct Answer & Explanation

. Wide surgical excision alone

Explanation

Chondrosarcomas are generally highly resistant to both chemotherapy and radiation therapy due to their poor vascularity and dense extracellular matrix. For intermediate-to-high grade (Grade II and III) chondrosarcomas, the standard of care is definitive wide surgical excision alone. Intralesional curettage is reserved for benign cartilaginous lesions (enchondromas) or select well-differentiated (Grade I) chondrosarcomas in the appendicular skeleton.

Question 2246

Topic: 10. Pathology and Oncology

A 32-year-old female presents with a painless, slowly enlarging mass behind her knee. The radiograph is shown.

Biopsy confirms a low-grade, bone-forming tumor on the surface of the posterior distal femur with a 'string sign' representing radiolucency between the tumor and the cortex. Which of the following genetic alterations is most classically associated with this diagnosis?

. t(11;22) chromosomal translocation
. t(X;18) chromosomal translocation
. GNAS gene mutation
. EXT1 gene mutation
. MDM2 and CDK4 gene amplification

Correct Answer & Explanation

. MDM2 and CDK4 gene amplification

Explanation

The clinical scenario and imaging description represent parosteal osteosarcoma, a low-grade surface osteosarcoma typically found on the posterior aspect of the distal femur. It is characterized molecularly by ring chromosomes and amplification of the 12q13-15 region, which includes the MDM2 and CDK4 genes. t(11;22) is associated with Ewing sarcoma. t(X;18) is seen in synovial sarcoma. GNAS mutations are found in fibrous dysplasia. EXT1 mutations are associated with hereditary multiple exostoses.

Question 2247

Topic: 10. Pathology and Oncology
A 14-year-old boy completes neoadjuvant chemotherapy for an osteosarcoma of the proximal tibia and undergoes a wide local excision. Pathologic evaluation of the resected specimen is performed. According to the Huvos grading system, what minimum percentage of tumor necrosis is the threshold to define a 'good response' to chemotherapy?
. 50%
. 75%
. 90%
. 95%
. 99%

Correct Answer & Explanation

. 90%

Explanation

The Huvos grading system evaluates the histologic response of osteosarcoma to neoadjuvant chemotherapy. A 'good response' is defined as 90% or greater tumor necrosis (Grade III is 91-99%, Grade IV is 100%). Less than 90% necrosis (Grades I and II) is considered a poor response and correlates with a worse overall prognosis.

Question 2248

Topic: 10. Pathology and Oncology

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

What is the single most important prognostic factor for his overall survival?

. Histologic subtype of the tumor
. Presence of metastatic disease at presentation
. Tumor size and volume at diagnosis
. Anatomic location of the primary tumor
. Alkaline phosphatase levels at diagnosis

Correct Answer & Explanation

. Presence of metastatic disease at presentation

Explanation

In osteosarcoma, the single most important prognostic factor for survival is whether metastatic disease is present at the time of diagnosis. For patients presenting with localized disease, the percentage of tumor necrosis following neoadjuvant chemotherapy (>90% necrosis indicates a good response) becomes the most important prognostic factor.

Question 2249

Topic: 10. Pathology and Oncology

A 24-year-old male presents with a slow-growing, painful soft tissue mass around the knee. Core needle biopsy reveals a biphasic tumor with both spindle cells and epithelial cells. What is the characteristic cytogenetic abnormality associated with this pathology?

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

Correct Answer & Explanation

. t(X;18)

Explanation

The patient has a biphasic synovial sarcoma. Synovial sarcoma is uniquely characterized by the t(X;18)(p11;q11) translocation, which results in the SYT-SSX fusion gene. t(11;22) is characteristic of Ewing sarcoma, t(9;22) is associated with myxoid chondrosarcoma (and CML), t(12;16) is seen in myxoid liposarcoma, and t(2;13) is seen in alveolar rhabdomyosarcoma.

Question 2250

Topic: Bone Tumors

Which variant of osteosarcoma is characteristically located on the surface of the bone, frequently involves the posterior cortex of the distal femur, features a heavily ossified broad base on imaging, and generally carries an excellent prognosis with wide surgical resection alone?

. Parosteal osteosarcoma
. Periosteal osteosarcoma
. High-grade surface osteosarcoma
. Telangiectatic osteosarcoma
. Intramedullary osteosarcoma

Correct Answer & Explanation

. Parosteal osteosarcoma

Explanation

Parosteal osteosarcoma is a low-grade surface tumor classically located at the posterior aspect of the distal femur. It presents as a dense, heavily ossified mass on a broad base. Due to its low-grade nature, it has the best prognosis among osteosarcoma subtypes, and wide surgical resection is typically curative without neoadjuvant chemotherapy. Periosteal osteosarcoma is intermediate-grade, often diaphyseal, with prominent chondroblastic features.

Question 2251

Topic: 10. Pathology and Oncology

A 28-year-old male presents with a slowly enlarging, painful soft tissue mass in his plantar foot. Biopsy reveals a biphasic spindle cell neoplasm with epithelial components. Which of the following chromosomal translocations is most characteristic of this tumor?

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

Correct Answer & Explanation

. t(X;18)

Explanation

The clinical picture and biphasic histology describe Synovial Sarcoma. This tumor is characterized by the t(X;18)(p11;q11) translocation, resulting in the SYT-SSX fusion gene. t(11;22) is seen in Ewing sarcoma, and t(12;16) is characteristic of myxoid liposarcoma.

Question 2252

Topic: Bone Tumors

A 14-year-old boy is undergoing neo-adjuvant chemotherapy for an osteosarcoma of the distal femur. His regimen includes Doxorubicin, Cisplatin, and high-dose Methotrexate. Which of the following is a classic dose-limiting toxicity specifically associated with Doxorubicin?

. Hemorrhagic cystitis
. Ototoxicity
. Dilated cardiomyopathy
. Peripheral neuropathy
. Pulmonary fibrosis

Correct Answer & Explanation

. Dilated cardiomyopathy

Explanation

Doxorubicin (Adriamycin) is heavily associated with cumulative, dose-dependent cardiotoxicity, specifically dilated cardiomyopathy. Cisplatin is classically associated with ototoxicity and nephrotoxicity. Ifosfamide is associated with hemorrhagic cystitis. Bleomycin is associated with pulmonary fibrosis.

Question 2253

Topic: 10. Pathology and Oncology

A 15-year-old male presents with chronic knee pain. Radiographs reveal an eccentric, lytic lesion confined to the epiphysis of the proximal tibia. A biopsy is performed.

Histological evaluation demonstrates mononuclear cells with grooved nuclei ('coffee bean' appearance) and areas of pericellular 'chicken-wire' calcification. What is the most likely diagnosis?

. Giant Cell Tumor
. Clear Cell Chondrosarcoma
. Chondroblastoma
. Aneurysmal Bone Cyst
. Osteoblastoma

Correct Answer & Explanation

. Chondroblastoma

Explanation

The diagnosis is Chondroblastoma, a benign but locally aggressive cartilaginous bone tumor that characteristically arises in the epiphysis or apophysis of long bones in skeletally immature or young adult patients. Histological hallmarks include mononuclear chondroblasts with grooved or clefted nuclei ('coffee bean' nuclei), multinucleated osteoclast-like giant cells, and fine lattice-like 'chicken-wire' pericellular calcifications.

Question 2254

Topic: 10. Pathology and Oncology

A 62-year-old male with multiple myeloma presents with thigh pain. Radiographs demonstrate an osseous lesion. When calculating the Mirels' score to determine the indication for prophylactic internal fixation, which of the following clinical or radiographic findings assigns the maximum of 3 points for its respective category?

. A purely blastic lesion
. A lesion involving the upper extremity
. Pain described as mild with weight-bearing
. A lesion diameter occupying greater than 2/3 of the bone cortex
. A lesion located in the diaphyseal shaft

Correct Answer & Explanation

. A lesion diameter occupying greater than 2/3 of the bone cortex

Explanation

The Mirels' classification evaluates four parameters to predict impending pathologic fracture: Site (Upper extremity=1, Lower extremity=2, Peritrochanteric=3), Pain (Mild=1, Moderate=2, Functional/Severe=3), Lesion character (Blastic=1, Mixed=2, Lytic=3), and Lesion size (<1/3 cortex=1, 1/3 to 2/3 cortex=2, >2/3 cortex=3). A score of 9 or greater indicates impending fracture requiring prophylactic fixation. Therefore, a lesion >2/3 of the cortex scores 3 points.

Question 2255

Topic: 10. Pathology and Oncology

An 11-year-old boy presents with a painful, swollen thigh. Imaging reveals a permeative diaphyseal lesion with an 'onion-skin' periosteal reaction. A biopsy confirms Ewing sarcoma. Which of the following cytogenetic abnormalities is most characteristically associated with this tumor?

. t(11;22)(q24;q12)
. t(9;22)(q34;q11)
. t(X;18)(p11;q11)
. t(2;13)(q35;q14)
. t(12;16)(q13;p11)

Correct Answer & Explanation

. t(11;22)(q24;q12)

Explanation

Ewing sarcoma is classically associated with the t(11;22)(q24;q12) chromosomal translocation, resulting in the EWS-FLI1 fusion protein in about 85% of cases. t(9;22) is seen in chronic myelogenous leukemia (Philadelphia chromosome). t(X;18) is associated with synovial sarcoma. t(2;13) is seen in alveolar rhabdomyosarcoma. t(12;16) is associated with myxoid liposarcoma.

Question 2256

Topic: 10. Pathology and Oncology



A 30-year-old male presents with a slow-growing, deep-seated, painful soft tissue mass in his left foot near the ankle joint. Imaging reveals a heterogeneous mass with stippled calcifications. Biopsy demonstrates a biphasic pattern consisting of spindle cells and epithelial cells. Which of the following cytogenetic abnormalities is classically associated with this tumor?

. t(11;22)(q24;q12)
. t(x;18)(p11;q11)
. t(9;22)(q22;q12)
. t(12;16)(q13;p11)
. t(2;13)(q35;q14)

Correct Answer & Explanation

. t(x;18)(p11;q11)

Explanation

The clinical, radiographic, and histologic descriptions are classic for synovial sarcoma. Synovial sarcoma is characterized by the specific chromosomal translocation t(X;18)(p11;q11), which results in the SYT-SSX fusion gene. This molecular marker is highly sensitive and specific for confirming the diagnosis.

Question 2257

Topic: 10. Pathology and Oncology



A 15-year-old boy presents with severe nocturnal thigh pain that awakens him from sleep but is dramatically relieved by NSAIDs. Radiographs show dense cortical thickening in the proximal femoral diaphysis. CT scan reveals a 6 mm radiolucent nidus surrounded by intense reactive sclerosis. Which of the following is true regarding the pathophysiology of this specific lesion?

. It produces high local levels of prostaglandins, particularly PGE2.
. It is characterized by germline mutations in the EXT1 or EXT2 genes.
. It carries a significant risk (approximately 5%) of malignant transformation.
. The radiolucent nidus must typically exceed 2 cm in diameter to cause pain.
. The classic night pain is mediated by histamine release from mast cells within the nidus.

Correct Answer & Explanation

. It produces high local levels of prostaglandins, particularly PGE2.

Explanation

Osteoid osteoma is a benign bone-forming tumor characterized by a radiolucent nidus usually less than 1.5-2 cm in diameter. The cells within the nidus produce very high levels of prostaglandins, particularly PGE2. This causes profound local vasodilation and severe pain, explaining the classic symptom of night pain that is rapidly and dramatically relieved by NSAIDs or aspirin.

Question 2258

Topic: Bone Tumors

A 16-year-old male presents with severe nocturnal thigh pain that is rapidly relieved by NSAIDs. Radiographs demonstrate a small radiolucent nidus surrounded by dense sclerotic reactive bone in the proximal femur. After failing medical management, which of the following is the most appropriate initial definitive treatment?

. Open intralesional curettage and bone grafting
. En bloc wide resection
. Radiofrequency ablation (RFA)
. External beam radiation therapy
. Observation with serial radiographs

Correct Answer & Explanation

. Radiofrequency ablation (RFA)

Explanation

The classic presentation of an osteoid osteoma is night pain relieved by NSAIDs, characterized radiographically by a radiolucent nidus with surrounding sclerosis. Radiofrequency ablation (RFA) is the standard of care for definitive minimally invasive treatment when medical management fails.

Question 2259

Topic: 10. Pathology and Oncology

A 55-year-old male undergoes excision of a large cartilaginous tumor of the proximal femur. Molecular analysis of the tumor reveals a mutation in the isocitrate dehydrogenase 1 (IDH1) gene. This mutation is a hallmark of and most frequently associated with which of the following conditions?

. Ollier disease
. Multiple Hereditary Exostoses
. Neurofibromatosis type 1
. Familial Adenomatous Polyposis
. McCune-Albright syndrome

Correct Answer & Explanation

. Ollier disease

Explanation

Mutations in the IDH1 and IDH2 genes are heavily implicated in the pathogenesis of cartilaginous tumors. Somatic mosaic mutations in these genes are found in over 80% of patients with Ollier disease and Maffucci syndrome, both of which are forms of enchondromatosis. Multiple Hereditary Exostoses is associated with EXT1/EXT2 mutations. McCune-Albright is associated with GNAS mutations. NF1 is associated with the neurofibromin gene.

Question 2260

Topic: Bone Tumors

A 14-year-old patient with high-grade conventional osteosarcoma is undergoing a neo-adjuvant chemotherapy regimen (MAP: Methotrexate, Doxorubicin, Cisplatin).

Which of the following is the most significant, dose-limiting toxicity specific to Doxorubicin?

. Nephrotoxicity
. Ototoxicity
. Cardiomyopathy
. Peripheral neuropathy
. Hemorrhagic cystitis

Correct Answer & Explanation

. Cardiomyopathy

Explanation

Doxorubicin (Adriamycin) is an anthracycline whose primary, irreversible dose-limiting toxicity is dilated cardiomyopathy, which is dependent on the cumulative lifetime dose. A baseline echocardiogram is mandatory before administration. Cisplatin is known for ototoxicity and nephrotoxicity. High-dose methotrexate requires leucovorin rescue and can cause mucositis, hepatotoxicity, and renal toxicity.

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