ABOS Part I Comprehensive Review - Batch 99

Question 1

A 28-year-old female presents with a 6-month history of worsening knee pain and swelling. She has a known history of a giant cell tumor (GCT) of the distal femur treated with extended curettage and adjuvant phenol 3 years prior. Recent MRI reveals a

Accepted Answer

Stage 3 (Aggressive)

Question 2

A 55-year-old male presents with a rapidly growing, painful mass in his posterior thigh. Biopsy confirms a high-grade undifferentiated pleomorphic sarcoma (UPS). MRI demonstrates the tumor originating in the deep posterior compartment, with clear ext

Accepted Answer

Stage IIB

Question 3

A 17-year-old male is diagnosed with a high-grade osteosarcoma of the proximal tibia. Initial staging MRI shows the tumor is confined to the proximal tibia, without cortical breach or soft tissue extension. However, a CT scan of the chest reveals mul

Accepted Answer

Stage III

Question 4

Which of the following anatomical locations or scenarios, when involved by a primary bone or soft tissue sarcoma, inherently classifies the tumor as extracompartmental (T2) in the Enneking system?

Accepted Answer

A tumor in the gluteal compartment that has caused a pathological fracture

Question 5

A 40-year-old male presents with a suspected high-grade sarcoma of the mid-femoral diaphysis. An initial biopsy was performed by a general surgeon using a transverse incision across the anterior thigh. Subsequent staging MRI shows tumor contamination

Accepted Answer

It converts an intracompartmental (T1) tumor to an extracompartmental (T2) tumor, necessitating a wider resection.

Question 6

A 35-year-old patient presents with a painful, enlarging mass in the distal tibia. Plain radiographs show a lytic lesion. For precise local staging of this suspected bone sarcoma, particularly regarding its true extent within the bone marrow and its

Accepted Answer

Magnetic Resonance Imaging (MRI) with contrast

Question 7

A 60-year-old male presents with acute pain and inability to bear weight after a minor fall. X-rays reveal a pathologic fracture of the proximal femur through a large lytic lesion. Biopsy confirms a high-grade osteosarcoma. Prior imaging (before the

Accepted Answer

It changes the local extent from intracompartmental (T1) to extracompartmental (T2).

Question 8

A 20-year-old patient with a high-grade osteosarcoma of the distal femur undergoes comprehensive staging. MRI shows the primary tumor confined to the distal femur. However, a whole-body bone scan reveals a separate, discontinuous focus of increased u

Accepted Answer

It automatically upstages the tumor to Stage III.

Question 9

A 48-year-old female presents with a 6 cm, slowly growing, deep-seated soft tissue mass in her anterior thigh. Biopsy reveals a low-grade myxofibrosarcoma. MRI shows the tumor is entirely confined within the anterior fascial compartment, without invo

Accepted Answer

Stage IA

Question 10

A 15-year-old male with a high-grade osteosarcoma of the distal femur undergoes neoadjuvant chemotherapy. After completion of chemotherapy, the resected specimen shows 95% tumor necrosis. While this is a critical prognostic indicator, how does this f

Accepted Answer

It is a critical prognostic factor, influencing adjuvant therapy, but does not alter the initial Enneking surgical stage.

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Key Takeaway