Biology, Genetics & Bone Healing MCQs

A 32-year-old woman presents with a lytic epiphyseal lesion in her proximal tibia. Biopsy confirms Giant Cell Tumor (GCT) of bone. Because the tumor is deemed unresectable, medical therapy is initiated. The prescribed medication targets which of the following?

A 30-year-old female presents with a large, lytic, expansile lesion in the proximal tibia extending to the subchondral bone. Biopsy demonstrates mononuclear cells interspersed with osteoclast-like multinucleated cells. Which targeted pharmacological agent can be used to downstage this tumor prior to surgery?

A 4-year-old girl is diagnosed with ANA-positive oligoarticular Juvenile Idiopathic Arthritis (JIA). What is the most critical routine screening required for this patient?

A 32-year-old woman presents with an expansive, purely lytic lesion in the distal radius extending to the subchondral bone. Biopsy confirms a Giant Cell Tumor (GCT). For an unresectable or recurrent GCT, which targeted medical therapy is most appropriate?

A 32-year-old woman presents with knee pain. Radiographs reveal an eccentric, purely lytic, epiphyseal lesion extending to the subchondral bone of the proximal tibia. Biopsy confirms multinucleated giant cells in a background of mononuclear stromal cells. Which targeted therapy acts as a RANKL inhibitor and is indicated for advanced or unresectable forms of this tumor?

A 32-year-old woman presents with knee pain. Radiographs reveal an eccentric, expansile lytic lesion in the distal femoral epiphysis extending to the articular surface. Biopsy shows multinucleated giant cells in a stroma of mononuclear cells. Which of the following is the most appropriate targeted medical therapy?

A 65-year-old man presents with severe back pain and fatigue. Radiographs show multiple "punched-out" lytic lesions in his skull and vertebral bodies. Laboratory studies reveal hypercalcemia, anemia, and an M-spike on serum protein electrophoresis. The osteolytic lesions in this disease are primarily mediated by the upregulation of which factor?

A 4-year-old girl with ANA-positive oligoarticular Juvenile Idiopathic Arthritis (JIA) presents for routine follow-up. Which of the following represents the most critical routine screening recommendation for this patient?

A 30-year-old female presents with a lytic lesion in the distal femur extending to the subchondral bone. Biopsy confirms a Giant Cell Tumor. Prior to extended intralesional curettage, the surgeon administers denosumab. What is the mechanism of action of denosumab?

A 32-year-old woman presents with a large, lytic, epiphyseal-metaphyseal lesion of her distal radius. Biopsy confirms a Giant Cell Tumor of bone (GCTB). She is started on Denosumab prior to surgical intervention. What is the mechanism of action of this medication?

A 4-year-old girl is evaluated for recurrent long bone fractures after minimal trauma, blue sclerae, and early hearing loss. Which of the following best describes the underlying biochemical defect?

A 25-year-old male presents for a routine orthopedic evaluation following a minor injury. On examination, he is noted to have a highly unusual ability to appose his shoulders anteriorly in the midline. He also has delayed secondary tooth eruption. A mutation in which gene is most likely responsible?

A 7-year-old boy presents with bilateral hip pain, a waddling gait, and short stature. Radiographs demonstrate delayed ossification of the capital femoral epiphyses and a double-layer patella on the lateral knee view. A mutation in which of the following is most likely responsible?

A newborn presents with micromelic short stature, severe clubfeet, hitchhiker thumbs, and cystic swelling of the external ears. Which of the following genes is mutated in this condition?

An 8-year-old girl with a history of multiple fractures, blue sclerae, and hearing loss is started on pamidronate therapy. What is the primary mechanism of action of this medication in her condition?

A 6-year-old child presents with a history of multiple low-energy fractures, progressive vision loss, and pancytopenia. Radiographs show diffusely dense bones with a 'bone-within-a-bone' appearance and Erlenmeyer flask deformity of the femurs. The underlying defect primarily involves impaired function of which cell type?

A 40-year-old male undergoes marginal excision of a nodular, plaque-like cutaneous mass on the trunk. Pathology returns as dermatofibrosarcoma protuberans (DFSP), demonstrating a t(17;22) translocation. Which targeted therapy is FDA-approved for unresectable or metastatic DFSP?

A 5-year-old child with blue sclerae, dentinogenesis imperfecta, and multiple prior fractures is started on intravenous pamidronate for osteogenesis imperfecta. What is the primary mechanism of action of this medication in this patient?

A 10-year-old patient presents with a prominent forehead, hypertelorism, and the ability to touch their shoulders together anteriorly. Radiographs reveal delayed cranial suture closure and aplastic clavicles. A mutation in which gene is the primary cause of this condition?

In secondary fracture healing, chondrocytes play a vital role. What is their primary contribution to the callus formation process?