10. Pathology and Oncology MCQs

A 45-year-old woman presents with weakness in wrist extension and finger extension. MRI demonstrates a large mass composed uniformly of fat sitting intimately on the periosteum of the proximal radius. What is the most likely diagnosis?

A 30-year-old male with a history of primary synovial chondromatosis of the hip undergoes arthroscopic synovectomy. Ten years later, he presents with sudden, rapidly progressive hip pain and an enlarging mass. Radiographs show aggressive bone destruction. What is the most likely diagnosis?

An osteochondroma is generally considered to stop growing at skeletal maturity. If an osteochondroma-like lesion originates within the epiphysis rather than the metaphysis, leading to joint deformity and restricted motion, what is this condition termed?

A painless soft tissue mass in the posterior neck of a 55-year-old man is biopsied. Histology reveals mature adipocytes, uniform spindle cells, and thick, rope-like collagen bundles without lipoblasts. Immunohistochemistry is strongly positive for CD34. What is the diagnosis?

A 35-year-old male presents with a slowly enlarging, painless mass over the distal femur. Radiographs reveal a sessile bony exostosis pointing away from the joint. An MRI is obtained to evaluate the cartilage cap. Which of the following cartilage cap thicknesses is most indicative of malignant transformation to secondary chondrosarcoma in an adult?

A 40-year-old female presents with progressive knee pain and mechanical catching. Imaging reveals multiple intra-articular calcified loose bodies with relative preservation of the joint space. A diagnosis of primary synovial chondromatosis is suspected. What is the underlying pathogenesis of this condition?

A 60-year-old male presents with a large, deep-seated fatty mass in the thigh. Biopsy shows mature adipose tissue with focal atypia and hyperchromatic stromal cells. Cytogenetic analysis is ordered to differentiate an Atypical Lipomatous Tumor (ALT) from a benign lipoma. Which of the following genetic markers is characteristic of an ALT?

A 10-year-old boy presents with multiple bony bumps around his knees, ankles, and shoulders. He is short in stature and exhibits a mild forearm deformity. A diagnosis of Multiple Hereditary Exostoses (MHE) is made. What is the inheritance pattern and the most common genetic mutation associated with this condition?

A 60-year-old male presents with a deep intramuscular mass in the thigh. MRI reveals a large lipomatous lesion with thick septations.

Core needle biopsy shows adipocytes with variation in cell size and hyperchromatic stromal cells. Which of the following cytogenetic abnormalities is diagnostic for this tumor?

A 45-year-old male complains of chronic knee pain, swelling, and catching. Radiographs and MRI are shown.

What is the primary pathophysiological mechanism underlying this condition?

A 40-year-old female presents with a painless, slow-growing mass on her proximal forearm. Radiographs demonstrate focal cortical hyperostosis of the proximal radius adjacent to a radiolucent soft-tissue mass. What is the most likely diagnosis?

A 25-year-old male with a known distal femur osteochondroma presents with a rapidly enlarging, pulsatile popliteal mass and calf pain.

What is the most likely etiology of the new mass?

A 45-year-old male incidentally undergoes a radiograph of his foot after a mild sprain. The lateral view shows a well-defined lytic lesion in the calcaneus with central calcification creating a target sign. What is the appropriate management?

A 15-year-old boy presents with a hard mass on his proximal tibia. Radiographs show a sessile bony exostosis pointing away from the joint space.

Which radiographic finding is required to definitively classify this lesion as an osteochondroma?

A 35-year-old male is evaluated for a large, deep intramuscular thigh mass. Core needle biopsy confirms the presence of well-differentiated adipocytes, but the pathologist requests fluorescence in situ hybridization (FISH) to differentiate between a benign lipoma and an atypical lipomatous tumor (ALT). Amplification of which of the following gene loci is pathognomonic for ALT?

A 45-year-old male presents with recurrent catching and locking in his left knee. Imaging reveals numerous uniformly sized, small calcified bodies confined within the joint capsule.

What is the most definitive histological hallmark distinguishing this condition from secondary osteochondromatosis?

A 14-year-old girl is evaluated for a painless, hard mass about the medial aspect of the proximal tibia.

Radiographs and MRI confirm the diagnosis of an osteochondroma. Which of the following imaging features is an absolute requirement to confidently make this diagnosis?

A 35-year-old male with long-standing primary synovial chondromatosis of the hip presents with rapid worsening of pain and joint swelling over the last three months. MRI reveals permeative destruction of the femoral neck with marrow replacement and a large soft tissue mass breaking through the joint capsule. What complication has most likely occurred?

A 52-year-old male is referred for a painless, slow-growing soft tissue mass in his proximal forearm. MRI reveals a well-defined lipomatous mass located entirely within the belly of the brachioradialis muscle. Biopsy demonstrates mature adipocytes interdigitating with normal skeletal muscle fibers, without cytological atypia or lipoblasts. Which of the following statements regarding this lesion is true?

An 18-year-old male presents with a pulsatile mass and a palpable thrill in the popliteal fossa of his right knee. He has a known history of a distal femur osteochondroma in the same leg. What is the most likely etiology of this vascular presentation?