Hyung-Jin Kim MD, Presenter: Nothing to Disclose

Eunhee Kim MD, Abstract Co-Author: Nothing to Disclose

Yoon Duck Kim, Abstract Co-Author: Nothing to Disclose

Kyung In Woo, Abstract Co-Author: Nothing to Disclose

Sung Tae Kim MD, Abstract Co-Author: Nothing to Disclose

Subconjunctival fat prolapse and dermolipoma of the orbit are two distinct, uncommon pathologic entities. They are rather unfamiliar to the radiologists and yet should be differentiated from each other, because their pathogenesis and treatment are quite different. The purpose of this study is to introduce our experiences on the CT and MR imaging findings that can distinguish subconjunctival orbital fat prolapse and dermolipoma.

Between 1995 and 2009, the search of the electronic database in our hospital revealed surgically proved 33 patients (27 males, 6 females; age range, 43-81 years; mean, 63 years) with subconjunctival orbital fat prolapse and 44 patients (9 males, 36 females; age range, 3-47 years; mean, 17 years) with dermolipoma. Among them, 8 patients with subconjunctival orbital fat prolapse and 7 patients with dermolipoma underwent CT and/or MR examinations. We retrospectively reviewed CT and MR images in these patients.

In all of 8 patients with subconjunctival orbital fat prolapse, CT and MR images demonstrated the herniated fat, continuous with the intraconal fat, between the lateral rectus muscle and the eyeball, either bilaterally (n=7) or unilaterally (n=1). In contrast, all of 7 patients with dermolipoma had a unilateral, crescentic (n=3) or triangular (n=4) fatty mass, anterior to the lateral rectus muscle and the eyeball, with no connection with the intraconal fat on CT and MR images.

The characteristic CT and MR imaging findings easily help discriminate between subconjunctival orbital fat prolapse and dermolipoma, both of which usually present as an epibulbar fatty mass in the lateral canthal area.

Although unfamiliar to the radiologists, subconjunctival orbital fat prolapse and dermolipoma are two distinct entities that should be differentiated from each other because of different management.

Kim, H, Kim, E, Kim, Y, Woo, K, Kim, S, Subconjunctival Fat Prolapse and Dermolipoma of the Orbit: Differentiation on CT and MR Imaging.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9008241.html