aCase 17a

by Dr.Chua

This 9-year old boy presented with a 2-year history of prominent left eye (Figure 1). Recently there had been an increase in size. His vision was normal in both eyes. Closure of the left eye was near complete with only minimal conjunctival exposure. Orbital examination revealed a non-axial proptosis which was no reducible (Hertel's exophthalmometer at 98mm Right eye 17mm and left eye 21 mm). The lateral aspect of the globe was red with subconjunctival pigmented, raised lesions which were not tender to palpation. The proptosis did not increase in size with Valsalva maneuver. The ocular motility showed restricted left horizontal movement more with abduction than adduction.

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 lesions 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 vascular spaces lined by endothelium laden with clotted blood. His parents refused surgical debulking because of the risk of visual loss.

Figure 3. Lobulated subconjunctival pigmented lesions.

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 in this patient?

Orbital lymphangioma. Despite the histology indicative of haemangioma, the CT scan picture, history and the gross morphology are consistent with orbital lymphangioma.

Lymphangioma is a rare, diffusely infiltrating benign vascular tumour, most commonly diagnosed in the first or second decade of life. Orbital involvement may include the lids, conjunctiva or orbit.

Histologically, the lesion contains irregularly shaped vascular spaces lined by endothelium, with the characteristics of blood or lymphatic vessels embedded in a fibrous stroma containing occasional lymphoid follicles. There may be old hemorrhage in the form of hemosiderin and cholesterol clefts. Thrombosis and calcification may be seen. The lymphoid follicles may proliferate during viral infections, resulting in worsening proptosis when the child has an upper respiratory tract infection.

The CT scan typically shows poorly circumscribed mass lesion which may be intraconal or extraconal or both. Calcification may be seen and fluid level representing haemorrhage of variable age is characteristic of lymphangioma.

b. What are the treatment options?

Surgical excision is the treatment of choice. Successful surgical resection have been reported but for the majority of cases, the surgical results are not always satisfactory. Due to the diffused infiltrating nature of the lesion, total resection of the orbital lymphangioma is difficult. Injury to nerve or muscle tissue can compromise the visual acuity or impair ocular motility. Cicatrisation from the resection may itself poses a cosmetic problem. Recurrence cases may require repeated resection. In our patient, no resection either partial or complete is performed as the parents are concerned about the visual consequences. However, if the lesion were to enlarge to such an extent that it causes visual problem either through optic nerve compression or exposure keratopathy, resection can then be undertaken.

In patients with sudden increase in proptosis, one needs to consider haemorrhage into cystic spaces. Needle aspiration can evacuate the blood and reduce the proptosis.

Apart from surgery, the use of oral steroid has been reported to reduce the proptosis. This is thought to reduce the lymphoid component of the lesion. The steroid needs to be given long term and may not be ideal for growing children.

Recently, intralesional injection of OK-432 (group A Streptococcus pyogenes of human origin which is used as an anticancer agent) has been reported to shrink orbital lymphangioma.

References:

1. TUNC M., SADRI E., CHAR D.H. − Orbital lym-phangioma: an analysis of 26 patients. Br. J.Ophthalmol., 1999, 83, 76-80.

2. Harris GJ, Sakol PJ, Bonavolonta G. An analysis of thirty cases of orbital lymphangioma. Ophthalmology 1990;97:1583–92.

3. Sires BS, Goins CR, Anderson RL, Holds JB. Systemic corticosteroid use in orbital lymphangioma. Ophthal Plast Reconstr Surg. 2001 Mar;17(2):85-90.

3. Suzuki Y et al. Management of orbital lymphangioma using intralesional injection of OK-432 Br J Ophthalmol 2000;84:614–617.