10. Pathology and Oncology MCQs

A 16-year-old boy presents with aching pain in his right anterior tibia that worsens at night. The pain is completely relieved by ibuprofen. A CT scan reveals a 0.8 cm radiolucent nidus surrounded by dense sclerotic bone. The intense pain experienced by this patient is primarily mediated by high local concentrations of which substance?

A 15-year-old boy presents with shoulder pain. Radiographs reveal a radiolucent, eccentrically located epiphyseal lesion in the proximal humerus with a thin sclerotic margin. Biopsy shows polygonal chondroblasts and characteristic "chicken-wire" calcification. What is the most likely diagnosis?

A 15-year-old girl presents with a rapidly expanding, painful mass in her proximal tibia. MRI reveals an eccentric, metaphyseal lesion with multiple fluid-fluid levels. Biopsy confirms an aneurysmal bone cyst (ABC). Primary ABCs are most frequently driven by a specific genetic rearrangement involving which of the following genes?

A 14-year-old male presents with chronic right knee pain. Radiographs reveal a well-circumscribed, lytic lesion in the proximal tibial epiphysis. A core needle biopsy is performed. Histologic examination demonstrates sheets of mononuclear cells with grooved 'coffee bean' nuclei, scattered multinucleated giant cells, and areas of pericellular 'chicken-wire' calcification. Which of the following is the most appropriate definitive management?

A 32-year-old female presents with a deep, painless, firm mass in her posterior thigh. Biopsy reveals a proliferation of uniform spindle cells in a dense collagenous stroma without cellular atypia or frequent mitoses. Immunohistochemistry is strongly positive for nuclear beta-catenin. In sporadic cases of this specific condition, which of the following genetic alterations is most frequently identified?

A 55-year-old male is diagnosed with a 10 cm high-grade myxofibrosarcoma of the deep anterior thigh. A multidisciplinary tumor board recommends surgical resection and radiation therapy. Based on randomized clinical trial data comparing preoperative versus postoperative radiation therapy for extremity soft tissue sarcomas, what is the most significant difference between the two approaches?

A 24-year-old male presents with a slowly enlarging, deep-seated mass near his knee joint. An initial core needle biopsy demonstrates a biphasic tumor with both epithelial and spindle cell components. Which of the following cytogenetic abnormalities is most characteristic of this soft tissue sarcoma?

A 16-year-old male successfully underwent extended curettage and bone grafting for a proximal humerus chondroblastoma 3 years ago. He now presents for a routine follow-up. While chondroblastoma is classified as a benign primary bone tumor, which of the following rare complications necessitates surveillance imaging in select cases?

A 28-year-old pregnant female notices a slowly enlarging mass in her right abdominal wall. Core biopsy confirms desmoid fibromatosis. The mass is mildly uncomfortable but causes no functional deficit. What is the currently accepted first-line management strategy for this patient?

When performing an incisional or core needle biopsy for a suspected extremity soft tissue sarcoma, which of the following technical principles is most critical to avoid compromising the definitive surgical resection?

A 35-year-old female presents with a 4 cm deep soft tissue mass in her foot. Pathology reveals nests of polygonal cells with clear cytoplasm separated by delicate fibrous septa. Immunohistochemistry is positive for HMB-45 and S-100 protein. Which of the following is the most likely diagnosis?

A 17-year-old male presents with shoulder pain. Radiographs reveal an eccentrically located, lytic epiphyseal lesion in the proximal humerus with a thin sclerotic rim. His physes are nearly closed. Based on the typical location and patient age, what is the most likely diagnosis?

A patient with progressive, unresectable extra-abdominal fibromatosis (desmoid tumor) is enrolled in a clinical trial. They are prescribed Nirogacestat, which recently demonstrated significant efficacy in the DeFi phase 3 trial. What is the mechanism of action of this targeted therapy?

A 62-year-old male presents with a massive, painless mass deep in his thigh. Core needle biopsy demonstrates a lipomatous tumor with fibrous septa and scattered atypical hyperchromatic stromal cells. Which molecular finding is pathognomonic and routinely used to distinguish this well-differentiated liposarcoma from a benign lipoma?

A 23-year-old male presents with a firm, deep-seated nodule in his volar forearm, initially misdiagnosed as a ganglion cyst. Histology shows a nodular growth pattern of epithelioid and spindle cells with central necrosis, mimicking a granuloma. Which immunohistochemical marker is classically LOST in this specific soft tissue sarcoma?

A 68-year-old female undergoes MRI for a slowly growing subcutaneous mass in her distal thigh. The MRI reveals a multinodular superficial mass with a distinct curvilinear 'tail' extending longitudinally along the fascial planes. Biopsy confirms myxofibrosarcoma. Because of this specific imaging and growth characteristic, what clinical challenge is most frequently encountered in the surgical management?

While most soft tissue sarcomas metastasize hematogenously to the lungs, a select subset has a higher propensity for lymphatic spread, necessitating routine clinical evaluation of regional lymph nodes. Which of the following sarcomas is included in this distinct subgroup?

A patient is undergoing staging for a newly diagnosed high-grade soft tissue sarcoma of the proximal thigh. Which of the following is the most appropriate imaging modality for evaluating the primary tumor for local surgical planning?

In the surgical management of a high-grade soft tissue sarcoma of the extremity without planned adjuvant radiation, what constitutes an 'adequate' oncologic margin to minimize the risk of local recurrence?