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Figure 1
Questions 1 and 2 refer to the following case.
A 21-year-old man presents with worsening right knee pain after a minor twisting injury playing basketball 3 months ago. The patient reports increased swelling along the posterior aspect of his knee and generalized leg edema on the right side. His pain is exacerbated by weight-bearing activities and deep knee flexion. The patient denies night pain, fevers, chills, or recent weight loss. His past medical history is significant for unilateral retinoblastoma, which was treated with minimal residual visual deficit. A technetium bone scan depicts an isolated lesion located in the right distal femur, and magnetic resonance imaging (MRI) shows sparing of the neurovascular bundle. A plain radiograph of the distal femur is shown in Figure 1.
1. What is the cause of this patient’s knee pain?
- Chondromyxoid fibroma
- Chondrosarcoma
- Ewing’s sarcoma
- Osteochondroma
- Osteosarcoma
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2. How should this patient be treated?
- Above the knee amputation
- Curettage and bone grafting
- Wide resection and chemotherapy
- Wide resection and radiotherapy
- Wide resection only
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Questions 3 and 4 refer to the following case.
A 9-year-old boy presents with a chief complaint of worsening focal left groin pain. The patient and family report recent weight loss but no fevers. Activities involving hip rotation have become increasingly difficult. Initially, aspirin relieved the pain, and the patient was able to sleep through the night; however, now the pain is refractory to daily nonsteroidal anti-inflammatory drugs (NSAIDs). Plain radiographs reveal an 8-mm well-circumscribed lesion with a sclerotic border and central radiolucent nidus.
3. What is this patient’s diagnosis?
- Aneurysmal bone cyst
- Brodie’s abscess
- Femoral neck stress fracture
- Fibrous dysplasia
- Osteoid osteoma
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4. Which of the following is the most appropriate treatment for this patient’s lesion?
- Chemotherapy
- Curettage, cryotherapy, and bone grafting
- Low-dose focal irradiation (600-800 cGy)
- Percutaneous radiofrequency ablation (RFA)
- Resection and prosthetic replacement
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5. A 9-year-old girl with a past history of precocious puberty and premature vaginal bleeding presents with a 6-month history of vague hip and ankle pain. On physical examination, the patient has hyperpigmented skin lesions (café au lait spots) with irregular borders and mild hip and ankle pain. Radiographs reveal polyostotic "ground-glass" lesions in the proximal femur and distal tibia. What is this patient’s most likely diagnosis?
- Gardner’s syndrome
- Hand-Schüller-Christian disease
- Letterer-Siwe disease
- McCune-Albright syndrome
- Paget’s disease
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Figure 2
6. A 16-year-old boy presents with a 6-month history of worsening pain and swelling in his left arm. He has had night fevers and an elevated erythrocyte sedimentation rate. An anteroposterior radiograph of the left humerus is performed, and histologic evaluation of a sample obtained from a needle biopsy reveals small round blue cells (Figure 2). Cytogenic evaluation is likely to show which of the following chromosomal translocations?
- t(8;14)
- t(11;22)
- t(9;22)
- t(X;18)
- t(17;22)
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Figure 3
7. A 65-year-old man presents with the insidious onset of atraumatic left shoulder pain. He reports recent weight loss but no significant medical history. On physical examination, he has pain with range of motion of the shoulder and a palpable/painful fullness in the left shoulder. An anteroposterior radiograph of the left shoulder is performed (Figure 3). Histologic evaluation of the lesion reveals multiple densely packed hyperchromatic cells per lacunae, and immunohistochemical S-100 protein stain is positive. What is this patient’s most likely diagnosis?
- Chondroblastoma
- Chondrosarcoma
- Desmoplastic fibroma
- Multiple myeloma
- Osteosarcoma
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