Figure 1. Left proptosis with redness of the left lateral globe in A.
Subconjunctival pigmented lesions could be seen in B.
C-F show restricted left horizontal movement more
with abduction than adduction.
Orbital CT scan (Figure 2) revealed a diffused orbital mass involving the left rectus muscle and the retrobulbar space. Occasional calcification was also identified within the mass. The radiologist gave a list of differential diagnosis including rhabdomyosarcoma (unlikely in view of the prolonged history).
Figure 2. CT scans of the orbit show near homogenous mass involving the lateral orbit
and the retrobulbar space. The lateral rectus can not be separated from the mass.
A biopsy of the lateral orbital mass (Figure 3 and 4) was reported as showing capillaries lined by endothelium laden with blood consistent with haemangioma. His parents refused surgical debulking because of the risk of visual loss.
Figure 4. Pigmented lesions with fibrous tissue in the lateral aspect of the lateral rectus.
The muscle was bound to the lesion by collagenous tissues.
a. What is the correct diagnosis for this condition?
b. What are the treatment options?