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10. Pathology and Oncology MCQs

Practice Set 153 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 3041

Topic: 10. Pathology and Oncology

The Mirels' classification is utilized to estimate the risk of pathologic fracture in metastatic bone disease. Which of the following is NOT a parameter included in the Mirels' scoring system?

. Site of the lesion
. Pain characteristics
. Nature of the lesion (lytic, blastic, mixed)
. Size of the lesion relative to bone cortex
. Histologic grade of the primary tumor

Correct Answer & Explanation

. Histologic grade of the primary tumor

Explanation

Mirels' criteria evaluate the risk of pathologic fracture based on four factors: site (upper vs lower extremity, peritrochanteric), pain level, nature of the lesion (blastic, mixed, lytic), and size relative to cortex thickness. Histologic grade is not included.

Question 3042

Topic: 10. Pathology and Oncology

A 28-year-old man presents with a deep-seated, slowly growing mass in his plantar foot. Biopsy reveals a biphasic tumor with both epithelial and spindle cell components. Immunohistochemistry is positive for epithelial membrane antigen (EMA) and cytokeratin. What is the characteristic chromosomal translocation associated with this diagnosis?

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

Correct Answer & Explanation

. t(X;18)

Explanation

Synovial sarcoma classically exhibits a t(X;18) chromosomal translocation, resulting in the SYT-SSX fusion gene. It often presents in young adults as a slow-growing mass in the extremities, classically around the foot or knee.

Question 3043

Topic: 10. Pathology and Oncology

A 35-year-old man presents with a painful mass around his knee. Biopsy reveals a biphasic tumor with spindle cells and epithelial cells. Which of the following chromosomal translocations is most characteristic of this lesion?

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

Correct Answer & Explanation

. t(X;18)

Explanation

Synovial sarcoma typically presents in young adults as a painful mass near a joint. It is characterized by the t(X;18)(p11;q11) translocation, which fuses the SYT gene with SSX1 or SSX2.

Question 3044

Topic: Bone Tumors

A 12-year-old boy presents with severe, unrelenting mid-shaft thigh pain that is worse at night and relieved by NSAIDs. Radiographs show a small radiolucent nidus with surrounding dense reactive sclerosis. What is the primary mediator responsible for the nocturnal pain?

. Interleukin-1 (IL-1)
. Tumor necrosis factor alpha (TNF-alpha)
. Prostaglandin E2 (PGE2)
. Vascular endothelial growth factor (VEGF)
. Basic fibroblast growth factor (bFGF)

Correct Answer & Explanation

. Prostaglandin E2 (PGE2)

Explanation

The clinical and radiographic presentation is classic for an osteoid osteoma. The nidus secretes high levels of PGE2, which mediates the characteristic night pain that responds well to NSAIDs.

Question 3045

Topic: 10. Pathology and Oncology

A 15-year-old boy is diagnosed with a conventional high-grade osteosarcoma of the distal femur. Molecular analysis of the tumor is most likely to reveal mutations in which of the following genes?

. EXT1
. GNAS
. TP53
. FGFR3
. COL1A1

Correct Answer & Explanation

. TP53

Explanation

Alterations in tumor suppressor genes such as TP53 and RB1 are frequently implicated in the pathogenesis of conventional osteosarcoma. Patients with Li-Fraumeni syndrome (germline TP53 mutation) have a markedly increased risk of developing this malignancy.

Question 3046

Topic: 10. Pathology and Oncology

A 30-year-old woman has a slow-growing soft tissue mass in her foot. Biopsy reveals a biphasic tumor with both epithelial and spindle cell components. Which of the following chromosomal translocations is highly specific for this diagnosis?

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

Correct Answer & Explanation

. t(x;18)

Explanation

The patient has a synovial sarcoma, which is characterized by the t(X;18) translocation resulting in the SYT-SSX fusion gene. It commonly presents as a deep-seated soft tissue mass in the extremities of young adults.

Question 3047

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with worsening knee pain over 2 months. Radiographs show a sunburst periosteal reaction in the distal femur. Biopsy reveals malignant mesenchymal cells producing osteoid matrix. Mutations in which of the following tumor suppressor genes are most commonly associated with this pathology?

. p53 and Rb
. APC and beta-catenin
. BRCA1 and BRCA2
. PTEN and NF1
. EXT1 and EXT2

Correct Answer & Explanation

. p53 and Rb

Explanation

Osteosarcoma is frequently associated with mutations in the Rb (retinoblastoma) and p53 tumor suppressor genes, as seen in hereditary syndromes like Li-Fraumeni. EXT genes are associated with multiple hereditary exostoses.

Question 3048

Topic: 10. Pathology and Oncology

A 65-year-old man presents with severe back pain, anemia, hypercalcemia, and elevated creatinine. Radiographs show multiple punched-out lytic lesions in his skull and pelvis. Which of the following diagnostic studies is most definitive for confirming his underlying condition?

. Serum alkaline phosphatase
. Serum protein electrophoresis and bone marrow biopsy
. Dual-energy x-ray absorptiometry (DEXA)
. Technetium-99m bone scan
. Urine levels of N-telopeptide

Correct Answer & Explanation

. Serum protein electrophoresis and bone marrow biopsy

Explanation

The clinical picture describes multiple myeloma (CRAB criteria: hyperCalcemia, Renal failure, Anemia, Bone lesions). Diagnosis is confirmed by a monoclonal spike on SPEP/UPEP and >10% clonal plasma cells on bone marrow biopsy.

Question 3049

Topic: 10. Pathology and Oncology

A 12-year-old girl has a painful, rapidly expanding mass in her distal humerus. MRI demonstrates a multiloculated, expansile lesion with fluid-fluid levels. Biopsy reveals blood-filled spaces lacking an endothelial lining. Which genetic abnormality is characteristic of the primary form of this lesion?

. t(11;22) translocation
. t(12;16) translocation
. MDM2 amplification
. t(16;17) translocation involving the USP6 gene
. GNAS mutation

Correct Answer & Explanation

. t(16;17) translocation involving the USP6 gene

Explanation

Primary Aneurysmal Bone Cysts (ABCs) are driven by a USP6 gene translocation, most commonly t(16;17). They present as expansile lytic lesions with classic fluid-fluid levels on MRI.

Question 3050

Topic: 10. Pathology and Oncology

A 10-year-old boy presents with a diaphyseal mass in his fibula. Radiographs reveal a permeative lesion with an onion-skin periosteal reaction. Histology demonstrates small round blue cells. The pathogenesis of this tumor is most commonly driven by which fusion protein?

. EWS-FLI1
. SYT-SSX1
. BCR-ABL
. PAX3-FKHR
. TLS-CHOP

Correct Answer & Explanation

. EWS-FLI1

Explanation

Ewing sarcoma is a malignant small round blue cell tumor characterized by the t(11;22) translocation, which produces the EWS-FLI1 fusion protein. The onion-skin periosteal reaction is a classic radiographic hallmark.

Question 3051

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with a painful mass around his distal femur. Biopsy reveals malignant spindle cells producing unmineralized osteoid. Which of the following genetic abnormalities is most commonly associated with the pathogenesis of this disease?

. t(11;22) translocation
. Mutation of the Rb and p53 genes
. t(X;18) translocation
. GNAS1 mutation
. t(12;16) translocation

Correct Answer & Explanation

. Mutation of the Rb and p53 genes

Explanation

Osteosarcoma is frequently associated with mutations in tumor suppressor genes such as Retinoblastoma (Rb) and p53 (Li-Fraumeni syndrome).

Question 3052

Topic: 10. Pathology and Oncology

A 9-year-old girl complains of progressive left leg pain and fever. Radiographs show a permeative diaphyseal lesion in the fibula with an "onion-skin" periosteal reaction. Immunohistochemistry of the biopsy specimen is positive for CD99. What is the most expected cytogenetic abnormality?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma is characterized by the t(11;22) translocation resulting in the EWS-FLI1 fusion protein, and typically shows strong membranous CD99 staining.

Question 3053

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with progressive knee pain over 2 months. Radiographs demonstrate a destructive metaphyseal lesion of the distal femur with a 'sunburst' periosteal reaction.

Biopsy confirms the diagnosis. What is the most appropriate definitive management for this condition?

. Radiation therapy followed by wide resection
. Neoadjuvant chemotherapy, wide surgical resection, and adjuvant chemotherapy
. Intralesional curettage, adjuvant phenol, and cementation
. Primary amputation without chemotherapy
. Observation with serial radiographs

Correct Answer & Explanation

. Neoadjuvant chemotherapy, wide surgical resection, and adjuvant chemotherapy

Explanation

Osteosarcoma is a high-grade spindle cell tumor that produces malignant osteoid. The standard of care includes neoadjuvant chemotherapy, wide surgical resection with negative margins, and adjuvant chemotherapy to address systemic micrometastases.

Question 3054

Topic: 10. Pathology and Oncology

A 9-year-old boy presents with mid-thigh pain and fevers. Radiographs show a diaphyseal permeative lytic lesion with an 'onion-skin' periosteal reaction.

Histological evaluation demonstrates uniform, small blue cells. Which chromosomal translocation is most characteristically associated with this tumor?

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

Correct Answer & Explanation

. t(11;22)

Explanation

Ewing sarcoma is a highly aggressive small round blue cell tumor. It is genetically defined by the t(11;22) chromosomal translocation in approximately 85% of cases, which fuses the EWS gene to the FLI1 gene.

Question 3055

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with a high-grade intramedullary osteosarcoma of the distal femur. A representative histological sample is shown.

Which of the following genetic alterations is most frequently associated with the pathogenesis of this specific bone tumor?

. t(11;22) translocation
. t(X;18) translocation
. Mutation of the p53 tumor suppressor gene
. Amplification of the MDM2 gene
. t(12;16) translocation

Correct Answer & Explanation

. Mutation of the p53 tumor suppressor gene

Explanation

Mutations in the p53 tumor suppressor gene and the retinoblastoma (Rb) gene are the most common genetic abnormalities found in conventional osteosarcoma. In contrast, t(11;22) is characteristic of Ewing sarcoma, and t(X;18) is pathognomonic for synovial sarcoma.

Question 3056

Topic: 10. Pathology and Oncology

Tumor-induced osteomalacia (oncogenic osteomalacia) is a rare paraneoplastic syndrome most commonly caused by benign phosphaturic mesenchymal tumors. It is characterized by renal phosphate wasting due to the overproduction of:

. Fibroblast growth factor 23 (FGF-23)
. Parathyroid hormone-related peptide (PTHrP)
. 1,25-dihydroxyvitamin D
. Calcitonin
. Sclerostin

Correct Answer & Explanation

. Fibroblast growth factor 23 (FGF-23)

Explanation

Tumor-induced osteomalacia is driven by the ectopic overproduction of FGF-23 by the tumor cells. High levels of FGF-23 inhibit sodium-phosphate cotransporters in the proximal renal tubule, leading to profound phosphaturia and subsequent osteomalacia.

Question 3057

Topic: 10. Pathology and Oncology

A 32-year-old woman presents with a slow-growing mass in her foot. Biopsy reveals a biphasic spindle cell neoplasm. Which of the following chromosomal translocations is most characteristic of this tumor?

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

Correct Answer & Explanation

. t(X;18)

Explanation

Synovial sarcoma is characterized by the t(X;18) translocation, resulting in the SYT-SSX fusion gene. It often presents in young adults as an indolent mass in the extremities, frequently near joints but rarely intra-articular.

Question 3058

Topic: Bone Tumors
A 9-year-old girl presents with a pathologic fracture of her proximal femur. Radiographs demonstrate a "ground-glass" appearance and a Shepherd's crook deformity. She also has irregular café-au-lait spots and precocious puberty. What is the underlying genetic mutation?
. EXT1
. GNAS
. TP53
. RB1
. FGFR3

Correct Answer & Explanation

. GNAS

Explanation

This clinical picture describes McCune-Albright syndrome, which features polyostotic fibrous dysplasia, endocrine abnormalities, and café-au-lait spots. It is caused by an activating mutation in the GNAS gene, leading to increased intracellular cAMP.

Question 3059

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with progressive knee pain and swelling. Radiographs show a permeative diaphyseal lesion with "onion-skin" periosteal reaction.

Biopsy shows small round blue cells. The most common chromosomal abnormality associated with this condition is a translocation between which two chromosomes?

. 11 and 22
. 12 and 16
. 9 and 22
. X and 18
. 2 and 13

Correct Answer & Explanation

. 11 and 22

Explanation

Ewing sarcoma typically presents in the diaphysis of long bones in children and young adults. It is strongly associated with the t(11;22) translocation, creating the EWS-FLI1 fusion protein.

Question 3060

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with worsening knee pain. Plain radiographs show a metaphyseal lesion with a sunburst periosteal reaction and Codman's triangle. To definitively diagnose conventional osteosarcoma, what essential histopathologic feature must be identified?

. Prominent woven bone without osteoblastic rimming
. Sheets of small round blue cells
. Malignant spindle cells producing osteoid
. Atypical chondrocytes in lacunae
. Biphasic epithelial and spindle cells

Correct Answer & Explanation

. Malignant spindle cells producing osteoid

Explanation

The hallmark of conventional osteosarcoma is the production of osteoid (immature bone matrix) directly by malignant mesenchymal cells. Woven bone without osteoblastic rimming is characteristic of fibrous dysplasia.

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