Answers

1. Orbital dermolipoma. Computed tomography of the orbits shows a hypodense, lentiform mass of size 1.1 Χ 0.5 cm giving fat attenuation [Figure 2]. It is medial to the lacrimal gland, anterior to the insertion of lateral rectus without any calcification in it. On magnetic resonance imaging, it is hyperintense on T1-[Figure 3] and T2-weighted imaging [Figure 4] and showed suppression on fat saturated imaging. Histopathology showed presence of squamous epithelium and adipose tissue.

Figure 2: Computed tomography of the orbit showing the lentiform, hypodense mass (arrow) Click here to view

Figure 3: T1-weighted magnetic resonance image showing the hyperintense mass Click here to view

Figure 4: T2-weighted magnetic resonance image showing the hyperintense mass Click here to view

2. The differential diagnoses of fat-containing epibulbar masses are limbal dermoid, subconjunctival fat prolapse and lipoma.

Discussion

Dermolipoma is presumed to be a congenital solid choristoma developing due to sequestration of the ectoderm in the conjunctiva at the time of embryonic development of the eyelid. ^[1] The commonest location for both subconjunctival fat prolapse and dermolipoma is the lateral canthal area below the temporal or superotemporal bulbar conjunctiva. Subconjunctival fat prolapse affects elderly obese men and presents as a unilateral or bilateral soft yellowish mass having a convex anterior margin which becomes prominent with retropulsion of the globe. On the contrary, dermolipoma is a congenital lesion with a female preference and presenting early in life. It manifests as a unilateral soft or firm pinkish-yellow mass with a straight or slightly concave anterior margin. It is frequently accompanied by fine hairs on the surface. It is not freely movable, cannot be repositioned into the orbit, and lesion size is not affected by retropulsion of the globe. ^[2] Histologically, dermolipoma show stratified squamous epithelium and various amounts of collagenous connective tissue and a disproportionate amount of adipose tissue in the subepithelial stroma. Surgical resection of dermolipoma should be done conservatively as wide or complete excision may cause complications which are unacceptable for an essentially cosmetic problem. ^[1]