Practice Set 169 of 351
This practice set contains high-yield board review questions covering key concepts in 10. Pathology and Oncology. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.
A 30-year-old female presents with a low-grade osteosarcoma located on the posterior surface of the distal femur. What gene amplification is characteristically identified in this tumor?
. MDM2
A patient with NF1 undergoes an excisional biopsy of a symptomatic soft tissue mass. Histology reveals S-100 positive spindle cells with wavy nuclei in a myxoid stroma. What is the most appropriate classification of this tumor?
. Neurofibroma
A 10-year-old boy is found to have a well-circumscribed, eccentrically located, lytic lesion with a sclerotic margin in the distal tibial metaphysis on an incidental radiograph. He is asymptomatic. What is the most appropriate management?
. Observation and reassurance
A 16-year-old male is undergoing treatment for localized high-grade conventional osteosarcoma of the proximal tibia. Following completion of neoadjuvant chemotherapy, surgical resection is performed. Which of the following findings is the most significant indicator of a poor overall prognosis?
. Less than 90% tumor necrosis in the resection specimen
A 12-year-old boy presents with thigh pain, fever, and a large diaphyseal mass in the femur with an "onion skin" periosteal reaction. Core needle biopsy demonstrates sheets of small round blue cells. Which chromosomal translocation is most characteristic of this diagnosis?
. t(11;22)(q24;q12)
A 3-year-old girl with a known diagnosis of Neurofibromatosis Type 1 presents with the limb deformity shown in the provided clinical image.
This specific deformity most frequently progresses to which of the following complications if left untreated?
. Congenital pseudarthrosis of the tibia (CPT)
A 28-year-old male with a history of Neurofibromatosis Type 1 presents with a rapidly enlarging and newly painful mass in his left thigh. He has had a long-standing, painless plexiform neurofibroma in this location since childhood. What is the estimated lifetime risk for patients with NF1 to develop a Malignant Peripheral Nerve Sheath Tumor (MPNST)?
. 8-10%
A 55-year-old male presents with deep pelvic pain. Imaging reveals a 12 cm destructive, permeative lytic lesion in the ilium with "popcorn" calcifications and cortical breakthrough. Biopsy confirms grade 3 conventional chondrosarcoma. What is the most appropriate primary treatment?
. Wide surgical excision alone
A 15-year-old male complains of right thigh pain that is significantly worse at night and dramatically improves 30 minutes after taking ibuprofen. Radiographs show a 1 cm radiolucent nidus surrounded by dense reactive sclerosis in the femoral diaphysis. What biochemical mediator is produced in excess by the central nidus, causing these classic symptoms?
. Prostaglandin E2 (PGE2)
. Serum and urine protein electrophoresis
A 16-year-old male presents with severe knee pain. Radiographs reveal a destructive, lytic metaphyseal lesion in the distal femur. MRI shows multiple fluid-fluid levels. Biopsy reveals highly pleomorphic, atypical spindle cells producing delicate, lacelike osteoid. What is the most likely diagnosis?
. Telangiectatic osteosarcoma
A 12-year-old boy presents with an aggressive diaphyseal mass in his femur. Biopsy reveals small, round blue cells positive for CD99. Which of the following chromosomal translocations is most strongly associated with this tumor?
. t(11;22)(q24;q12)
A 45-year-old male with a history of multiple hereditary exostoses (EXT1 mutation) reports a newly growing mass on his proximal humerus. MRI shows a cartilage cap thickness of 3.5 cm. What is the most likely histological finding in this secondary malignancy?
. Atypical chondrocytes with binucleation and host bone permeation
A 28-year-old woman with Neurofibromatosis Type 1 reports rapid enlargement and new onset severe resting pain in a long-standing thigh mass. MRI reveals a large, heterogeneous mass along the sciatic nerve with central necrosis. What is the most important prognostic factor for her likely diagnosis?
. Complete surgical resection with negative margins
A 19-year-old male complains of severe, aching pain in his right shin that is worse at night and relieved by ibuprofen. Radiographs show a dense cortical thickening with a small 6 mm radiolucent nidus. What is the primary pain-generating mechanism in this lesion?
. High local concentrations of Prostaglandin E2 (PGE2)
A 65-year-old male presents with back pain and a pathological fracture of the L4 vertebral body. Laboratory studies reveal hypercalcemia and anemia. Which of the following is the most appropriate next step in confirming the suspected diagnosis?
. Serum and urine protein electrophoresis
A 55-year-old man presents with an impending fracture of his right femur secondary to a lytic metastatic lesion. His primary cancer is known to be renal cell carcinoma. Before performing prophylactic internal fixation, which of the following interventions is most strongly recommended?
. Preoperative embolization of the lesion
A 15-year-old male presents with knee pain. Radiographs reveal a 2 cm eccentric, well-circumscribed, lytic lesion with a thin sclerotic rim located entirely within the distal femoral epiphysis. Histology shows polygonal chondroblasts and "chicken-wire" calcifications. What is the most common complication following intralesional curettage of this tumor?
. Local recurrence
A 25-year-old male presents with a slowly growing, painful soft tissue mass near his knee joint. Radiographs show fine stippled calcifications within the soft tissue mass. Biopsy reveals a biphasic pattern of spindle cells and epithelial cells. What is the associated cytogenetic abnormality?
. t(X;18) (SYT-SSX)
. It increases the risk of local tumor recurrence following intralesional curettage.