Practice Set 12 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.
Primary aneurysmal bone cysts (ABCs) are now recognized as true neoplasms. Which of the following genetic translocations is most frequently associated with primary ABCs?
. t(16;17)
An asymptomatic 12-year-old boy has an incidental radiograph of the knee showing an eccentric, multiloculated, radiolucent lesion with a sclerotic rim in the distal femoral metaphysis. What is the expected natural history of this lesion?
. Spontaneous resolution and ossification by adulthood
A 16-year-old male presents with deep thigh pain that is worse at night and dramatically relieved by ibuprofen. Radiographs show a small radiolucent nidus surrounded by dense reactive sclerosis in the proximal femur. Which imaging modality is best for localizing the nidus prior to ablation?
. Thin-slice CT scan
Histological evaluation of an osteoid osteoma nidus will most likely reveal which of the following?
. Interlacing trabeculae of woven bone rimmed by prominent osteoblasts in a vascular stroma
In a giant cell tumor (GCT) of bone, which cell type represents the true neoplastic component driving the proliferation?
. The mononuclear stromal cells
An 18-year-old presents with dull back pain not significantly relieved by NSAIDs. Imaging reveals an expansile 3.5 cm radiolucent lesion in the posterior elements of L3. Histology is identical to an osteoid osteoma. What is the most likely diagnosis?
. Osteoblastoma
A 25-year-old patient undergoes a radiographic workup for right thigh pain. The femur shows an intramedullary expansile lesion with a "ground-glass" appearance, cortical thinning, and bowing.
What is the most definitive molecular feature associated with this condition?
. GNAS gene missense mutation
. GNAS1
A 45-year-old female with known polyostotic fibrous dysplasia presents with a newly palpable, painless, deep soft tissue mass in her thigh. MRI shows a well-circumscribed, T2-hyperintense intramuscular mass. What is the most likely diagnosis of the soft tissue mass?
. Intramuscular myxoma
Which immunohistochemical marker is essential for differentiating adamantinoma from osteofibrous dysplasia in a tibial diaphyseal lesion?
. Cytokeratin
A 14-year-old male with polyostotic fibrous dysplasia presents with a progressive shepherd's crook deformity of the proximal femur and worsening hip pain. What is the most reliable surgical strategy to correct the deformity and prevent recurrence?
. Valgus osteotomy with intramedullary nailing
A 12-year-old girl undergoes imaging after a minor knee twist. An incidental finding on the radiograph shows a 2 cm eccentric, radiolucent lesion with a sclerotic margin in the distal femoral metaphysis. She is asymptomatic. What is the most appropriate management?
. Observation and reassurance
. Mental retardation, café-au-lait spots, and hypogonadism
A 9-year-old boy presents with acute arm pain after throwing a baseball. Radiographs show a centrally located, completely radiolucent metaphyseal lesion in the proximal humerus with a cortical fracture and a cortical fragment settling in the dependent portion of the lesion.
What is the most likely diagnosis?
. Unicameral bone cyst
A 15-year-old female presents with progressive knee pain. MRI reveals an eccentric metaphyseal lesion in the proximal tibia demonstrating multiple fluid-fluid levels on T2-weighted images.
Histology will most likely reveal which of the following?
. Blood-filled spaces lacking endothelial lining
Which of the following cytogenetic abnormalities is most frequently identified in primary aneurysmal bone cysts?
. USP6 gene rearrangement
. Post-zygotic activating mutation in the GNAS gene
Which of the following modalities is considered a strict contraindication in the management of an uncomplicated, painful fibrous dysplasia lesion?
. Radiation therapy
A 45-year-old woman with a history of polyostotic fibrous dysplasia presents with a painless, deep soft tissue mass in her right thigh. MRI reveals an intramuscular lesion with high T2 signal. Core needle biopsy demonstrates a hypocellular, myxoid stroma without cellular atypia. What is the most likely diagnosis?
. Intramuscular myxoma
A 7-year-old boy presents with anterior bowing of the tibia. Radiographs show a multi-loculated, radiolucent lesion confined to the anterior tibial cortex. Biopsy reveals woven bone trabeculae with prominent osteoblastic rimming in a fibrous stroma. What is the most likely diagnosis?
. Osteofibrous dysplasia