10. Pathology and Oncology MCQs

A 13-year-old girl presents with knee pain. MRI reveals a multiloculated, expansile metaphyseal lesion in the proximal tibia with prominent fluid-fluid levels. Biopsy confirms an Aneurysmal Bone Cyst (ABC). What primary genetic alteration is frequently associated with primary ABCs?

A 17-year-old male presents with dull, aching back pain that is not relieved by NSAIDs. Radiographs show a 3 cm expansile lesion in the posterior elements of L3. Biopsy reveals the following histology.

What is the most likely diagnosis?

An 8-year-old boy presents with a permeative lytic lesion in the diaphysis of the femur with a prominent periosteal reaction. Biopsy reveals sheets of uniform small round blue cells that are CD99 positive. Which specific chromosomal translocation is most characteristic of this tumor?

A 14-year-old boy with distal femoral osteosarcoma completes neoadjuvant chemotherapy and undergoes limb-salvage surgery. Which of the following is the most important independent prognostic factor for his long-term survival?

A 6-year-old girl presents with a limp, precocious puberty, and large, irregular cafe-au-lait spots on her torso. Radiographs show ground-glass appearing expansile lesions in her proximal femur resulting in a "shepherd's crook" deformity. What is the underlying genetic mutation?

A 7-year-old boy from Connecticut presents with a massive, painless right knee effusion. He is afebrile, weight-bearing, and has a WBC of 8,000 cells/mcL and an ESR of 25 mm/h. Joint aspiration reveals a WBC count of 45,000/mcL. Gram stain is negative. What is the most appropriate next step in diagnosis?

A 16-year-old male presents with chronic, dull back pain that is not completely relieved by NSAIDs. Radiographs show a 3 cm expansile lesion in the posterior elements of the lumbar spine. A biopsy is obtained, revealing loose fibrovascular connective tissue intermixed with irregular woven bone trabeculae and active osteoblasts, with no nuclear atypia.


Which of the following statements is true regarding this lesion?

A 12-year-old boy presents with severe, progressive knee pain. Radiographs reveal a mixed lytic and sclerotic lesion in the distal femoral metaphysis with a "sunburst" periosteal reaction and Codman's triangle. Core needle biopsy confirms high-grade, conventional osteosarcoma. Which of the following factors is most predictive of this patient's long-term survival?

An 8-year-old boy presents to the emergency department after a minor fall onto his arm. Radiographs demonstrate a pathologic fracture through a centrally located, purely radiolucent lesion in the proximal humeral metaphysis. A radiopaque fragment is noted resting at the dependent portion of the cyst (the "fallen leaf" sign). What is the most appropriate initial management for this presentation?

A 17-year-old male complains of chronic, dull back pain that is worse at night but has an inconsistent response to NSAIDs. A biopsy is obtained, and the histology demonstrates loose fibrovascular connective tissue intermixed with irregular osteoid and plump osteoblasts.

Which of the following clinical or radiographic features distinguishes this lesion from an osteoid osteoma?

An 8-year-old boy presents with an aggressive, permeative diaphyseal lesion in his femur with a classic 'onion-skin' periosteal reaction. A core needle biopsy is performed to confirm the diagnosis. Which immunohistochemical marker is most consistently positive in this specific tumor?

A 10-year-old girl complains of intermittent proximal tibial pain for 3 months. Laboratory tests show a normal WBC count and a slightly elevated ESR. Radiographs reveal a well-circumscribed lucency in the proximal tibial metaphysis surrounded by a thick sclerotic margin. What is the most likely diagnosis?

A 12-year-old boy presents with multiple painless, bony bumps over his knees and shoulders. Radiographs show sessile bony projections that are continuous with the medullary cavity of the host bone. Mutations in which of the following genes are responsible for this condition?

A 14-year-old girl gets an ankle radiograph after a mild sprain. An incidental eccentric, lucent, cortically-based lesion with a scalloped sclerotic border is found in the distal tibial metaphysis. She has no pain at the site. What is the most appropriate management?

A 14-year-old male is diagnosed with high-grade osteosarcoma of the distal femur. He undergoes 10 weeks of neoadjuvant chemotherapy followed by wide surgical resection. Pathologic analysis of the resected specimen reveals 95% tumor necrosis. What does this finding indicate?

A 12-year-old boy presents with knee pain and a large soft tissue mass around the proximal fibula. Biopsy reveals small round blue cells. Molecular analysis confirms a t(11;22) chromosomal translocation. Which fusion protein is typically generated by this translocation?

When performing an incisional biopsy of a suspected malignant primary bone tumor in the lower extremity, which of the following principles must be strictly adhered to?

A 55-year-old male presents with deep pelvic pain. Radiographs reveal a large, destructive lesion in the ilium with 'rings and arcs' calcification. Biopsy confirms conventional high-grade chondrosarcoma. What is the mainstay of treatment?

A 68-year-old man complains of severe lower back pain and fatigue. Radiographs show multiple 'punched-out' lytic lesions in his skull and pelvis. Which of the following tests is the most appropriate next step to confirm the suspected diagnosis?

A 19-year-old male reports right thigh pain that is worse at night and dramatically relieved by ibuprofen. Imaging shows a 0.8 cm radiolucent nidus surrounded by dense sclerotic bone in the femoral diaphysis. What is the treatment of choice if he fails medical management?