1. General Principles & Basic Science MCQs

A 68-year-old man presents with increasing hat size, hearing loss, and bowing of his tibiae. Laboratory tests show markedly elevated serum alkaline phosphatase with normal calcium and phosphorus. Histology of the affected bone would most likely show which of the following pathognomonic features?

A 24-year-old female presents with anterior chest wall pain, palmoplantar pustulosis, and severe acne. Radiographs of the sternoclavicular joint reveal hyperostosis and osteitis. Which of the following is the most appropriate initial pharmacological treatment for her osteoarticular symptoms?

A 30-year-old female presents with knee pain. Radiographs reveal an eccentric, lytic lesion in the distal femoral epiphysis extending to the subchondral bone without a sclerotic rim. Biopsy shows mononuclear stromal cells and multinucleated giant cells. Which of the following targeted therapies is most appropriate for advanced or unresectable cases of this tumor?

A 12-year-old girl presents with delayed eruption of secondary teeth and the ability to appose her shoulders anteriorly. Radiographs reveal absent clavicles and delayed ossification of the pubic symphysis. A mutation in which of the following transcription factors is most likely responsible?

A 9-year-old girl presents with recurrent episodes of multifocal bone pain and swelling, primarily affecting the clavicle and distal tibia. Laboratory tests show a mildly elevated ESR but normal WBC count. Blood cultures are negative, and a bone biopsy reveals sterile chronic inflammation. She also has palmoplantar pustulosis. What is the most appropriate initial pharmacological treatment?

A 35-year-old male presents with chronic, painless swelling of his right knee. MRI reveals a joint effusion with nodular synovial proliferation that demonstrates low signal intensity on both T1 and T2-weighted images, with a 'blooming' artifact on gradient-echo sequences. What is the characteristic histological finding of this condition?

An 65-year-old man presents with increasing hat size and deep, aching bone pain in his pelvis and right femur. Laboratory tests show markedly elevated serum alkaline phosphatase with normal calcium and phosphorus. Histological examination of the affected bone would most likely reveal:

In the surgical management of chronic bacterial osteomyelitis of the tibia, the surgeon identifies a segment of necrotic cortical bone that has become separated from the surrounding living bone. What is the correct anatomical term for this necrotic bone segment?

A 10-year-old girl presents with a painless snapping sensation in her lateral knee during extension. MRI confirms a complete (Wrisberg variant) discoid lateral meniscus. What is the primary anatomical deficiency in the Wrisberg variant of a discoid meniscus?

A 4-year-old child presents with painful soft tissue swellings over the back and neck following minor trauma. Clinical examination reveals a congenital malformation of the great toes (hallux valgus and microdactyly). Radiographs show early heterotopic ossification in the paraspinal muscles. A mutation in which of the following genes is most likely responsible for this condition?

A newborn is evaluated for severe limb shortening, rigid clubfeet, 'hitchhiker' thumbs, and cystic swelling of the external ear (cauliflower ear). Radiographs show short, thick tubular bones. Mutations in which of the following genes are responsible for this syndrome?

A 14-year-old boy reports nocturnal thigh pain that is completely relieved by ibuprofen. Imaging shows a 7 mm radiolucent nidus surrounded by reactive sclerosis in the proximal femur cortex. Which inflammatory mediator is characteristically secreted in high levels by this lesion?

A 12-year-old girl is noted to have a large head with delayed closure of fontanelles, dental anomalies, and the ability to appose her shoulders anteriorly. Radiographs show absent clavicles. What is the function of the protein encoded by the gene mutated in this condition?

A 32-year-old female presents with a destructive, expansile lytic lesion in the proximal tibia extending to the subchondral bone. Biopsy confirms Giant Cell Tumor of bone. She is treated with denosumab preoperatively. What is the specific molecular target of denosumab?

An 8-year-old boy is evaluated for a waddling gait and knee pain. He has normal spine radiographs with no evidence of platyspondyly, but appendicular skeleton films show irregular, delayed ossification of multiple epiphyses and a characteristic 'double-layered' patella. A mutation in which of the following genes is most likely responsible for his condition?

An 8-year-old child presents with delayed eruption of secondary teeth and an unusual ability to bring both shoulders together anteriorly. Radiographs demonstrate bilateral absent clavicles and coxa vara. A mutation in which of the following transcription factors is responsible for this condition?

A newborn presents with severe micromelic short stature, "hitchhiker" thumbs, clubfeet, and "cauliflower" ears. Genetic analysis reveals a mutation in the SLC26A2 gene. Which of the following best describes the underlying biochemical defect in this dysplasia?

A 26-year-old woman presents with knee pain. Imaging reveals an eccentric, expansile lytic lesion in the distal femoral epiphysis extending into the metaphysis, without a sclerotic rim. Biopsy confirms a giant cell tumor of bone. If medical therapy is considered for an unresectable lesion, which mechanism of action is targeted by the drug of choice?

A 12-year-old boy has an incidental finding on a knee radiograph taken for a sprain. The x-ray shows a 3 cm, eccentrically located, sharply demarcated, multi-loculated radiolucent lesion with a sclerotic rim in the distal tibial metaphysis. If a biopsy were performed, what would be the most likely histologic finding?

A 27-year-old male with a history of recurrent intra-abdominal and extremity soft tissue masses presents for evaluation. Biopsies have consistently shown desmoid fibromatosis. Due to this multifocal presentation, the patient should be urgently screened for mutations in which gene, associated with a potentially fatal gastrointestinal condition?