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10. Pathology and Oncology MCQs

Practice Set 154 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 3061

Topic: Bone Tumors

A 12-year-old girl complains of mild localized pain in her proximal humerus. Radiographs demonstrate an expansile, eccentric, multiloculated lucent lesion in the metaphysis. MRI shows multiple fluid-fluid levels. Primary aneurysmal bone cysts are most commonly associated with a rearrangement of which gene?

. GNAS
. EXT1
. USP6
. TP53
. COL1A1

Correct Answer & Explanation

. USP6

Explanation

Primary aneurysmal bone cysts (ABCs) are now recognized as genuine neoplasms driven by USP6 gene rearrangements (typically t(16;17)). This distinguishes primary ABCs from secondary ABCs that arise in preexisting tumors.

Question 3062

Topic: Soft Tissue Tumors & Metastasis

A 65-year-old man presents with a destructive, purely lytic lesion in the proximal humerus and a history of nephrectomy for renal cell carcinoma. He is scheduled for wide excision and prosthetic reconstruction. What is the most critical preoperative step to minimize intraoperative complications?

. Systemic chemotherapy
. Neoadjuvant radiation therapy
. Preoperative embolization of the lesion
. Bone marrow aspiration
. Administration of intravenous bisphosphonates

Correct Answer & Explanation

. Preoperative embolization of the lesion

Explanation

Renal cell and thyroid carcinoma bone metastases are notoriously hypervascular. Preoperative selective arterial embolization is critical to minimize massive, potentially life-threatening intraoperative hemorrhage.

Question 3063

Topic: 10. Pathology and Oncology

A 14-year-old girl is diagnosed with conventional osteosarcoma of the distal femur. Her family history is significant for a mother who had early-onset breast cancer and a brother with a soft tissue sarcoma. A mutation in which of the following tumor suppressor genes is most likely responsible for this familial presentation?

. p53
. Rb
. APC
. NF1
. EXT1

Correct Answer & Explanation

. p53

Explanation

Li-Fraumeni syndrome is an autosomal dominant condition caused by a mutation in the p53 tumor suppressor gene. It places patients at a high risk of developing osteosarcoma, breast cancer, and soft tissue sarcomas.

Question 3064

Topic: Bone Tumors

A 19-year-old man presents with nocturnal leg pain that is dramatically relieved by NSAIDs. A radiograph and CT scan demonstrate a small intracortical lucency with surrounding sclerosis in the tibial diaphysis.

What is the mechanism of action of the most appropriate minimally invasive treatment for this condition?

. Focal thermal coagulation via alternating current
. Cryoablation using argon gas
. Chemical necrosis via absolute alcohol injection
. Targeted embolization of feeding vessels
. Radiation-induced DNA cross-linking

Correct Answer & Explanation

. Focal thermal coagulation via alternating current

Explanation

The clinical and radiographic presentation is classic for an osteoid osteoma. Radiofrequency ablation (RFA), which uses alternating current to cause focal thermal coagulation and necrosis, is the minimally invasive treatment of choice.

Question 3065

Topic: 10. Pathology and Oncology

A 28-year-old man presents with a slow-growing, deep soft-tissue mass near his ankle joint. A biopsy reveals a biphasic pattern of spindle cells and epithelial cells. Which of the following chromosomal translocations is most characteristic of this diagnosis?

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

Correct Answer & Explanation

. t(X;18)

Explanation

Synovial sarcoma is characterized by the t(X;18) translocation, which results in the SYT-SSX fusion gene. It commonly presents as a deep soft-tissue mass near a joint in young adults and often exhibits a biphasic histologic pattern.

Question 3066

Topic: Bone Tumors

A 12-year-old girl presents with a rapidly expanding, painful mass in her proximal humerus. Radiographs show an expansile, multiloculated radiolucent lesion.

Genetic analysis of the tissue would most likely reveal an upregulation of which of the following?

. USP6
. GNAS
. EXT1
. RUNX2
. COL1A1

Correct Answer & Explanation

. USP6

Explanation

The presentation and imaging are consistent with a primary aneurysmal bone cyst (ABC). Primary ABCs are true neoplasms characterized by a t(16;17) translocation leading to USP6 gene upregulation.

Question 3067

Topic: 10. Pathology and Oncology

A 68-year-old man presents with diffuse back pain and fatigue. Laboratory tests show hypercalcemia, normocytic anemia, and an elevated creatinine. A skeletal survey reveals multiple punched-out lytic lesions in the skull and vertebrae. Which of the following is the most appropriate next step to confirm the diagnosis?

. Serum protein electrophoresis (SPEP) and bone marrow biopsy
. Technetium-99m whole-body bone scan
. Open biopsy of a vertebral lesion
. Prostate-specific antigen (PSA) test
. Parathyroid hormone (PTH) level

Correct Answer & Explanation

. Serum protein electrophoresis (SPEP) and bone marrow biopsy

Explanation

The clinical picture of CRAB symptoms (hyperCalcemia, Renal failure, Anemia, Bone lesions) is classic for multiple myeloma. SPEP, urine protein electrophoresis (UPEP), and a bone marrow biopsy are essential to detect the monoclonal protein spike and confirm the diagnosis.

Question 3068

Topic: Soft Tissue Tumors & Metastasis
A 5-year-old boy is diagnosed with Chondroectodermal Dysplasia. In addition to skeletal and cardiac anomalies, the orthopedic surgeon should be aware of the ectodermal manifestations of this disease. Which of the following dermatological or appendageal findings is commonly associated with this syndrome?
. Plantar keratoderma
. Alopecia totalis
. Café-au-lait macules
. Hyperhidrosis
. Neurofibromas

Correct Answer & Explanation

. Plantar keratoderma

Explanation

The 'ectodermal' component of Chondroectodermal Dysplasia (Ellis-van Creveld syndrome) includes anomalies of the hair, dystrophic nails, ichthyoids, and plantar keratoderma. Café-au-lait macules and neurofibromas are associated with Neurofibromatosis.

Question 3069

Topic: Soft Tissue Tumors & Metastasis
In addition to skeletal and cardiac abnormalities, patients with Ellis-van Creveld syndrome frequently exhibit ectodermal defects. Which of the following dermatological or ectodermal findings is commonly associated with this condition?
. Café-au-lait spots
. Plantar keratoderma
. Neurofibromas
. Port-wine stains
. Hypopigmented macules

Correct Answer & Explanation

. Plantar keratoderma

Explanation

Ectodermal manifestations of Ellis-van Creveld syndrome include dystrophic nails, anomalies of hair, ichthyoids, and plantar keratoderma.

Question 3070

Topic: Soft Tissue Tumors & Metastasis
A patient presents with the foot deformities shown in the clinical and radiographic images. In addition to these skeletal findings, which of the following dermatological manifestations is commonly associated with this syndrome?
. Café-au-lait spots
. Plantar keratoderma
. Subcutaneous neurofibromas
. Port-wine stains
. Ash-leaf spots

Correct Answer & Explanation

. Plantar keratoderma

Explanation

The image demonstrates shortening of the digits of the toes and feet, characteristic of Ellis-van Creveld syndrome. Associated ectodermal and dermatological findings in this disease include ichthyoids, plantar keratoderma, anomalies of hair, and dystrophic nails.

Question 3071

Topic: Soft Tissue Tumors & Metastasis
The clinical and radiographic images belong to a patient with chondroectodermal dysplasia. In addition to the skeletal anomalies shown, which of the following dermatological/ectodermal manifestations is commonly associated with this syndrome?
. Café-au-lait spots
. Plantar keratoderma
. Subcutaneous neurofibromas
. Port-wine stains
. Hypopigmented macules

Correct Answer & Explanation

. Plantar keratoderma

Explanation

Ellis-van Creveld syndrome (chondroectodermal dysplasia) is associated with several ectodermal anomalies. Alongside skeletal issues like shortening of the digits, patients frequently exhibit ichthyoids, plantar keratoderma, anomalies of the hair, and dystrophic nails.

Question 3072

Topic: Soft Tissue Tumors & Metastasis

The "ectodermal" component of Chondroectodermal Dysplasia (Ellis-van Creveld syndrome) is classically manifested by which of the following physical findings?

. Blue sclerae and hearing loss
. Alopecia universalis
. Anhidrosis and hyperthermia
. Hypoplastic or absent nails and neonatal teeth
. Cafe-au-lait spots and neurofibromas

Correct Answer & Explanation

. Hypoplastic or absent nails and neonatal teeth

Explanation

Ectodermal manifestations in EVC include hypoplastic, thin, or absent finger and toenails, as well as dental anomalies like neonatal teeth, partial anodontia, and delayed tooth eruption.

Question 3073

Topic: 10. Pathology and Oncology

A 48-year-old man with end-stage renal disease presents with a painful lytic lesion in his proximal tibia. Biopsy reveals a spindle cell stroma with numerous multinucleated giant cells and hemosiderin-laden macrophages. What is the most appropriate initial management of this bony lesion?

. Wide surgical resection
. Intralesional curettage and bone grafting
. Radiation therapy
. Medical management of the underlying endocrinopathy
. Amputation

Correct Answer & Explanation

. Medical management of the underlying endocrinopathy

Explanation

The histology describes a Brown tumor, characteristic of secondary hyperparathyroidism in renal failure. The primary treatment is medical management of the hyperparathyroidism (or parathyroidectomy if refractory), which leads to remineralization and healing of the tumor.

Question 3074

Topic: 10. Pathology and Oncology

A 72-year-old man with long-standing Paget's disease presents with a new onset of severe, unremitting thigh pain and a rapidly enlarging mass. Which of the following is the most likely histologic finding upon biopsy of the mass?

. Sheets of uniform, small round blue cells
. Chondrocytes in lacunae with binucleation
. Pleomorphic spindle cells producing osteoid
. Multinucleated giant cells in a hemorrhagic stroma
. Malignant plasma cells with eccentric nuclei

Correct Answer & Explanation

. Pleomorphic spindle cells producing osteoid

Explanation

The clinical presentation suggests secondary osteosarcoma, a rare but deadly complication of Paget's disease (occurring in about 1% of patients). Histologically, it is characterized by highly pleomorphic malignant spindle cells producing unmineralized bone matrix (osteoid).

Question 3075

Topic: 10. Pathology and Oncology

A 40-year-old female sustains a pathologic fracture of her humerus. Radiographs show a well-defined lytic lesion. Biopsy reveals numerous multinucleated giant cells, spindle cells, and extensive hemosiderin deposition.

Which laboratory test is most critical to differentiate this lesion from a primary giant cell tumor of bone?

. Serum protein electrophoresis
. Intact Parathyroid Hormone (PTH)
. Serum uric acid
. Bone-specific alkaline phosphatase
. 24-hour urine hydroxyproline

Correct Answer & Explanation

. Intact Parathyroid Hormone (PTH)

Explanation

The histologic description is consistent with a Brown tumor of hyperparathyroidism, which is histologically indistinguishable from a true giant cell tumor of bone. Evaluation of serum calcium, phosphorus, and intact PTH is essential to confirm hyperparathyroidism.

Question 3076

Topic: 10. Pathology and Oncology

A 72-year-old male with a long history of Paget's disease presents with a 2-month history of rapidly worsening, severe pain in his right thigh. Radiographs demonstrate a new destructive, lytic lesion in the previously thickened cortex of the femur.

What is the most likely diagnosis?

. Chondrosarcoma
. Osteosarcoma
. Ewing sarcoma
. Multiple myeloma
. Metastatic carcinoma

Correct Answer & Explanation

. Osteosarcoma

Explanation

The most common malignant transformation in Paget's disease is secondary osteosarcoma, presenting with new-onset severe pain and cortical destruction. Prognosis is generally poor compared to primary osteosarcoma.

Question 3077

Topic: 10. Pathology and Oncology

A 48-year-old female with chronic kidney disease presents with a lytic bone lesion in her distal femur. Laboratory studies reveal elevated parathyroid hormone (PTH) and hypercalcemia.

What is the most likely diagnosis of this lesion?

. Giant cell tumor
. Brown tumor
. Aneurysmal bone cyst
. Osteoblastoma
. Enchondroma

Correct Answer & Explanation

. Brown tumor

Explanation

Brown tumors are focal bone lesions associated with hyperparathyroidism, composed of osteoclasts and fibrous tissue. They histologically resemble giant cell tumors but occur in the setting of abnormal PTH and calcium metabolism.

Question 3078

Topic: 10. Pathology and Oncology

A 55-year-old female is diagnosed with primary hyperparathyroidism and is found to have a mechanically stable, asymptomatic Brown tumor in her proximal humerus. What is the most appropriate initial management for the bone lesion?

. En bloc resection and endoprosthetic reconstruction
. Curettage, phenol adjuvant, and bone grafting
. External beam radiation therapy
. Parathyroidectomy and observation of the lesion
. Intralesional corticosteroid injection

Correct Answer & Explanation

. Parathyroidectomy and observation of the lesion

Explanation

Brown tumors often remineralize and regress spontaneously following successful treatment of the underlying hyperparathyroidism (e.g., parathyroidectomy). Surgical intervention for the bone lesion is reserved for impending or actual pathologic fractures.

Question 3079

Topic: 10. Pathology and Oncology

A biopsy is taken from a lytic bone lesion in a patient with severe untreated secondary hyperparathyroidism. What is the classic histologic appearance of this lesion?

. Sheets of monotonous plasma cells with eccentric nuclei
. Multinucleated giant cells in a fibrovascular stroma with prominent hemosiderin
. Atypical chondrocytes arranged in lobules with myxoid stroma
. Spindle cells arranged in a classical herringbone pattern
. Pleomorphic mesenchymal cells producing delicate osteoid lace

Correct Answer & Explanation

. Multinucleated giant cells in a fibrovascular stroma with prominent hemosiderin

Explanation

Histologically, Brown tumors consist of multinucleated giant cells interspersed in a highly vascular, fibrous stroma. Prominent hemosiderin deposition from microhemorrhages imparts the macroscopic "brown" color.

Question 3080

Topic: Bone Tumors

A 70-year-old female with a long-standing history of polyostotic Paget's disease presents with new-onset, severe, and unrelenting pain in her right thigh. Radiographs demonstrate a new destructive, lytic lesion in previously pagetoid bone. What is the most likely diagnosis?

. Chondrosarcoma
. Multiple myeloma
. Ewing sarcoma
. Secondary osteosarcoma

Correct Answer & Explanation

. Secondary osteosarcoma

Explanation

Secondary osteosarcoma is a rare (approx. 1%) but highly lethal complication of Paget's disease. It typically presents as a rapid increase in localized pain and swelling, with radiographs showing a destructive bone lesion.

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