SEARCH

SEARCH BY CITATION

Sir,

A48-year-old woman complained of discrete, unilateral upper eyelid oedema that had been present for several years. She did not have exophthalmus or double vision. Her visual acuity was 20/20. The intraocular pressure and the anterior and posterior segment of both eyes were normal. The medical history was unremarkable except for arterial hypertension.

On ultrasonography of the left orbit, an intraorbital lesion of low reflectivity and with a well delineated cystic wall was detected in close proximity to the lacrimal gland. High resolution computed tomography (CT) revealed a craniolateral bony defect in the lateral orbital wall and a cystic intraorbital lesion extruding into the temporal fossa (Fig. 1).

image

Figure 1. High resolution computer tomography (HR-CT) demonstrating a full-size bony defect in the lateral orbital wall, with the two components of the dermoid cyst inside the orbit and the temporal fossa.

Download figure to PowerPoint

An anterior orbitotomy was performed, which demonstrated a dumbbell-shaped cystic lesion with a well defined fibrous capsule. The major part of it was located within the superolateral orbit, but it communicated with another part in the temporal fossa through a bony defect (Fig. 2). The lesion was completely excised. Histology revealed a dermoid cyst. The surgical outcome was satisfactory without double vision or enophthalmus.

image

Figure 2. Intraoperative situs with the two communicating components of the dumbbell-shaped dermoid cyst: one inside the orbit, through the lateral orbital wall and one in the temporal fossa.

Download figure to PowerPoint

Dermoid cysts are benign lesions of the orbit which represent about 6% of all orbital tumours (Shields et al. 2004). They are by far the most common orbital cystic lesions in childhood, accounting for over 40% of all orbital lesions in that age group, and for over 80% of all biopsied orbital lesions independent of age (Shields & Shields 2004). Unlike in simple epithelial cysts, the cyst wall is lined with surface epithelium with hair follicles or sweat glands in close proximity (Shields & Shields 2004).

Dermoid cysts are typically located subcutaneously along the orbital walls close to bony fissures and embryonic ossification centres. Superficial dermoid cysts often become manifest in the superotemporal orbit during childhood. Deep dermoid cysts manifest during adolescence or adulthood, with symptoms such as exophthalmus and double vision. They can be located as deep as the inferotemporal fossa (Perry & Tuthill 2003) or be intracerebral (Chen et al. 2003). In all, 85% of all dermoid cysts are associated with bony changes on CT (Meyer et al. 1999), such as notches or full thickness defects (Sathanathan et al. 1993).

Dermoid cysts with a dumbbell configuration are rare (Whitney et al. 1986; Sathanathan et al. 1993; Emerick et al. 1997; Meyer et al. 1999). In two cases, the patient suffered from chewing-induced visual impairment or mastification-induced proptosis. Our patient suffered only cosmetically from a discrete upper eyelid oedema. A dermoid cyst extruding into the temporal fossa was an unexpected diagnosis, especially when considering the age of the patient. The reason for the late manifestation might be its deep location and a slow increase in volume over the years.

During surgery, extraordinary care must be taken to avoid a rupture of the dermoid cyst. Otherwise, a persistant granulomatous intraorbital inflammation can occur (Sathanathan et al. 1993). The probability of rupture increases with the size of the dermoid cyst (Dithmar et al. 1993; Coevet et al. 2000). A dumbbell configuration represents a particular risk for peroperative rupture because of the firm adhesion to the periosteum within the bony channel.

Acknowledgements

  1. Top of page
  2. Acknowledgements
  3. References

We thank Gabriele Lengersdorff and Lisa Merz for their excellent photographic work.

References

  1. Top of page
  2. Acknowledgements
  3. References