Biology, Genetics & Bone Healing MCQs

A 72-year-old woman on long-term alendronate therapy for osteoporosis presents with atraumatic thigh pain. Radiographs reveal focal cortical thickening and a transverse radiolucent line on the lateral cortex of the subtrochanteric femur. What is the recommended management?

A 4-year-old boy presents with short stature, rhizomelic shortening of the limbs, and frontal bossing. Radiographs show narrowing of the interpedicular distances in the lumbar spine. Based on the classification of skeletal dysplasias with predominantly metaphyseal involvement, which of the following genetic mutations is most likely responsible for this condition?

A 6-year-old girl is brought to the clinic with a history of multiple low-energy fractures. Examination reveals blue sclerae and dentinogenesis imperfecta. Which of the following best describes the underlying pathophysiology of her condition?

A 12-year-old girl is evaluated for delayed dental eruption and the ability to bring her shoulders together anteriorly. Radiographs show absent clavicles and delayed ossification of the pubic symphysis. What is the inheritance pattern and associated gene mutation for this syndrome?

A 32-year-old female presents with knee pain. Radiographs show an eccentric, lytic epiphyseal-metaphyseal lesion in the distal femur extending to the subchondral bone. Biopsy reveals multinucleated giant cells in a background of mononuclear stromal cells. Which of the following targeted therapies is most appropriate for unresectable or recurrent cases of this tumor?

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 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?

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:

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 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 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 14-year-old boy presents with knee pain. Radiographs reveal a lytic lesion in the distal femoral epiphysis.

Biopsy is performed. Which histologic feature is diagnostic for this condition?

A 14-year-old boy presents with right shoulder pain. Radiographs reveal a well-defined lytic lesion in the proximal humeral epiphysis.

Histology shows mononuclear cells with grooved nuclei and areas of fine, pericellular calcification. Which of the following is the most appropriate definitive management?

Which histological feature is considered classic for chondroblastoma when examining tissue from an epiphyseal lytic lesion in an adolescent?