10. Pathology and Oncology MCQs

What is the most definitive pathognomonic radiographic and histologic feature of an osteochondroma?

A 60-year-old male is diagnosed with an atypical lipomatous tumor (ALT) in the deep posterior compartment of the thigh. There is no clinical or radiographic evidence of dedifferentiation. What is the most appropriate surgical treatment?

A 22-year-old male with a known, untreated osteochondroma of the distal posterior femur complains of a new, expanding pulsatile mass in the popliteal fossa and severe calf claudication. What is the most likely diagnosis?

A 16-year-old male presents with a painless, palpable mass about the distal femur.

Which radiographic finding is considered pathognomonic for this lesion?

A 55-year-old male presents with a large, slow-growing, deep-seated mass in the posterior thigh.

Biopsy demonstrates mature adipocytes with focal nuclear atypia. Which genetic alteration is most characteristic of this lesion?

Which clinical feature most reliably distinguishes Primary Synovial Chondromatosis from Secondary Synovial Chondromatosis?

A 25-year-old male with a known sessile osteochondroma of the proximal tibia reports a recent onset of pain and rapid growth of the mass. An MRI is obtained. Which finding most strongly suggests malignant transformation?

An incidental cartilaginous lesion is identified in the proximal humerus of a 50-year-old female. Which of the following MRI findings differentiates a low-grade chondrosarcoma from a benign enchondroma?

A 22-year-old male presents with a painless mass about his distal femur. Radiographs demonstrate a pedunculated exostosis pointing away from the joint.

Which of the following gene mutations and corresponding molecular mechanisms is most likely responsible for this condition?

A 45-year-old male presents with worsening knee pain and swelling after years of stable, mild discomfort. Radiographs reveal multiple uniformly sized periarticular calcified bodies.

MRI demonstrates a new, large, non-calcified soft tissue mass invading the adjacent femur. What is the most likely diagnosis of this new lesion?

A 55-year-old female undergoes a core needle biopsy of a deep, 10-cm intramuscular thigh mass.

Histology shows mature adipocytes with focal nuclear atypia. Which of the following molecular markers is most specific for distinguishing this lesion from a benign lipoma?

A 50-year-old female with a 10-year history of primary synovial chondromatosis of the knee presents with rapid worsening of pain, significant new swelling, and restricted motion. MRI demonstrates aggressive soft tissue expansion and new marrow invasion. What is the most likely cause of her acute deterioration?

A 60-year-old male presents with a deep, painless, slow-growing 10 cm mass in the posterior thigh. Core needle biopsy shows mature adipose tissue with scattered focal atypia and hyperchromatic stromal cells. Which molecular finding confirms the diagnosis of an atypical lipomatous tumor rather than a benign lipoma?

A 30-year-old male with a known solitary sessile osteochondroma of the distal femur presents with new-onset, progressive pain at the site. Which of the following MRI findings is most indicative of malignant transformation in a skeletally mature patient?

A general surgeon performs an unplanned excisional biopsy of an atypical lipomatous tumor located deep in the anterior thigh using a transverse incision. How does this initial approach primarily complicate the definitive orthopedic oncology management?

Pathological evaluation of a solitary sessile mass resected from the proximal humerus of a 14-year-old boy reveals host trabecular bone merging with a superficial cartilage cap. Which histologic feature of the cartilage cap characterizes it as a classic benign osteochondroma?

A 72-year-old male with a long-standing history of Paget's disease involving the right femur presents with new, progressive, unremitting thigh pain and a newly palpated soft tissue mass. Radiographs show aggressive cortical destruction. What is the most likely diagnosis?

A 72-year-old female with a long history of Paget's disease presents with a new, rapidly enlarging, painful mass in her proximal femur. Radiographs show cortical destruction and soft tissue extension. What is the most likely diagnosis?

A 70-year-old male with long-standing polyostotic Paget's disease presents with a sudden, severe increase in pain in his left femur accompanied by a rapidly enlarging soft tissue mass. What is the most likely diagnosis?

A 72-year-old male with a history of Paget's disease presents with a 2-month history of a rapidly enlarging, painful mass in his left proximal femur. Radiographs show a destructive lytic lesion with cortical breach. What is the most likely diagnosis?