Case Study: May 2009


A 10 year old boy presents with a left orbital mass and massive proptosis, causing exposure keratopathy leading to corneal perforation.

The orbital mass is surgically excised and was found to be in the orbital soft tissue, with no connection with the orbital bones.

Figure 1-low power scan
Figure 2 and 3 the cellular area
Figure 4-area of necrosis
Figure 5-showing tumour heterogeneity
Figure 6 and 7 showing some tumour features.


1. Figures 2 and 3 illustrate what?
2. What do figures 5, 6 and 7 illustrate?
3. What is the likeliest diagnosis?
4. What is the prognosis?

Click to show answers

1. They show undifferentiated small round blue cells with a haemangiopericytomatous vascular pattern.

2. Areas of malignant hyaline cartilage, ossification, in relation to the undifferentiated small round blue cells.

3. Extra-skeletal mesenchymal chondrosarcoma.

4. It is highly malignant with a strong tendency toward local recurrence and metastasis. The course is protracted and relentless. However, the orbital cases are said to have a better prognosis than those occurring elsewhere (this is based on a very small number of cases and may not be an accurate reflection).


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