1. General Principles & Basic Science MCQs

A 45-year-old male presents with painless swelling, severe destruction, and dislocation of his right shoulder joint. Radiographs show a disorganized, fragmented joint with significant bony debris. He has a history of a cervical spinal cord injury resulting in a progressive fluid collection within the cord. This shoulder pathology is most directly mediated by the loss of which of the following?

Histopathologic examination of a diaphyseal bone lesion shows irregular spicules of woven bone distributed within a bland fibrous stroma. A classic diagnostic feature of this pathology is the absence of which of the following?

A patient with syringomyelia complains of loss of pain and temperature sensation. Which specific anatomical tract is compromised to cause these unilateral or bilateral sensory deficits prior to dorsal column involvement?

A 22-year-old female with polyostotic fibrous dysplasia presents with new-onset, deep, aching bone pain in her affected femur, without evidence of acute fracture or deformity progression. Which pharmacological intervention has been shown to be most effective in alleviating this specific type of bone pain?

When performing surgical treatment on a standard, accessible aneurysmal bone cyst in the proximal tibia of a 15-year-old, the current standard of care to minimize local recurrence involves intralesional curettage followed by which critical intraoperative step?

A 12-year-old boy presents with a limp. Radiographs show a proximal femur lesion with a ground-glass appearance and a varus deformity. Which of the following genetic abnormalities is most likely responsible?

A 15-year-old male presents with back pain. Imaging shows an expansile, lytic lesion involving the posterior elements of L3. Biopsy reveals blood-filled cystic spaces lacking endothelial lining. Which of the following adjuvant therapies is most appropriate if the lesion is surgically inaccessible?

A 30-year-old woman with a known history of syringomyelia presents to the clinic with a cape-like distribution of sensory loss over her shoulders. Which specific sensory modalities are typically lost FIRST in this condition?

Fibrous dysplasia is driven by a somatic mutation in the GNAS gene. This mutation directly leads to the constitutive activation of which of the following cellular pathways?

Which of the following medical therapies is considered the most effective for the management of severe, recalcitrant bone pain associated with polyostotic fibrous dysplasia?

If left completely untreated, a progressively expanding cervical syringomyelia is most likely to eventually result in which of the following late neurologic complications?

In cases of surgically inaccessible or highly morbid aneurysmal bone cysts (e.g., within the sacrum), which targeted systemic therapy has shown significant efficacy in shrinking the lesion and promoting ossification?

A patient with syringomyelia presents with characteristic neurologic deficits in the upper extremities. Which of the following physical exam findings is most classically associated with a central cord syrinx?

In the treatment of a recurrent aneurysmal bone cyst (ABC) of the pelvis that is deemed surgically unresectable due to excessive morbidity, which of the following medical therapies is most appropriate?

A 10-year-old child presents with severe bone pain secondary to polyostotic fibrous dysplasia. Nonsteroidal anti-inflammatory drugs have provided minimal relief. What is the most appropriate first-line pharmacologic therapy for managing this patient's bone pain?

A 40-year-old female presents with an atypical subtrochanteric femur fracture characterized by transverse orientation, lateral cortical thickening, and a medial spike. Which of the following medications is most directly associated with the pathogenesis of this fracture pattern?

A 28-year-old woman presents with knee pain. Radiographs show an eccentric, expansile, purely lytic lesion in the distal femoral epiphysis extending to the subchondral bone. Histology reveals mononuclear cells and multinucleated osteoclast-like giant cells. What targeted medical therapy has been FDA-approved for unresectable cases of this tumor?

A 5-year-old boy presents with an ability to touch his shoulders together anteriorly. He has a wide, flat skull, delayed fontanelle closure, and a wide pubic symphysis on radiographs. This condition is caused by a mutation in a gene crucial for the differentiation of which cell type?

A 10-year-old boy presents with progressive knee pain. Imaging reveals a subchondral lucency in the proximal tibial epiphysis. A biopsy demonstrates sheets of mononuclear cells with a 'coffee bean' nucleus and longitudinal grooving, alongside eosinophils. Which immunohistochemical marker is characteristically positive in this lesion?