B. Osteosarcoma

B. Osteosarcoma:  

Is a malignant mesenchymal tumor in which tumor cells produce bone matrix. They are known to involve the metaphyses of long bones of extremities. They have a bimodal age distribution, most cases are seen in 10-14 years and a smaller peak is seen in adults above 40 years. The key radiological features include the Codman triangle and sunburst appearance on X-ray. 

History:

18-year-old male patient presented with a painful swelling in the left knee. 

Key Questions & Answers

1.Describe the gross features of the specimen

• 1. Lower end of femur with a gray white tumor in the medullary cavity

  2. Tumor is seen invading the cortex and periosteal tissue

2.Identify the microscopic features of the given slide

• 1. Pleomorphic round to oval tumor cells with hyperchromatic nuclei arranged in groups and sheets

  2. Eosinophilic tumor osteoid matrix seen between the cells

  3. Tumor giant cells, abnormal mitosis, calcification, haemorrhage and necrosis may be seen.

3.Diagnose the pathological condition correlating the history, gross and microscopic features

          Osteosarcoma 

4.Mention four most common sites of involvement

• 1. Lower end of femur

  2. Upper end of tibia

  3. Upper end of humerus

  4. Lower end of radius

5.What are the classical x-ray findings

• 1. Sunburst appearance

  2. Codman’s triangle