|Year : 2011 | Volume
| Issue : 4 | Page : 333-335
Different patterns of orbital roof involvement by cholesterol granuloma
Adel H Alsuhaibani1, Khalid Al-Rubaie1, Hattan Al-Khiary1, Jeffrey A Nerad2
1 Department of Ophthalmology, King Abdulaziz University Hospital, King Saud University, Riyadh, Saudi Arabia
2 Cincinnati Eye Institute, Cincinnati, Ohio, USA
|Date of Web Publication||23-Nov-2011|
Adel H Alsuhaibani
Department of Ophthalmology, King Abdulaziz University Hospital, King Saud University, PO Box 245, Riyadh 11411
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Two patients presented with cholesterol granuloma (CG), with completely different patterns of orbital roof involvement. One patient had a large intraorbital cystic CG, whereas the other had a very large intraosseous CG of the frontal bone. The presentation of CG with variable orbital roof involvement highlights the importance of being aware of the clinical characteristics and the imaging features of CG.
Keywords: Cholesteatoma, Cholesterol Granuloma, Orbital Roof, Proptosis
|How to cite this article:|
Alsuhaibani AH, Al-Rubaie K, Al-Khiary H, Nerad JA. Different patterns of orbital roof involvement by cholesterol granuloma. Middle East Afr J Ophthalmol 2011;18:333-5
|How to cite this URL:|
Alsuhaibani AH, Al-Rubaie K, Al-Khiary H, Nerad JA. Different patterns of orbital roof involvement by cholesterol granuloma. Middle East Afr J Ophthalmol [serial online] 2011 [cited 2019 Jun 27];18:333-5. Available from: http://www.meajo.org/text.asp?2011/18/4/333/90142
| Introduction|| |
Cholesterol granuloma (CG) is a rare condition caused by a foreign body reaction to cholesterol crystals. CG has been reported in several locations, such as the peritoneum, lungs, breast, lymph nodes, kidney, and testis.  Research has shown that in the head and neck region, CG mostly occurs in bony structures, such as the mastoid antrum and the air cells of the temporal bone.  CG can also occur in the jaw, nasal sinuses, and base of the skull.  Orbital involvement by CG is rare and usually occurs in the lateral portion of the superior orbital ridge, within the frontal diploic space. 
In this report, we describe the clinical, radiologic, and histopathologic features of two patients with orbital CG who presented with completely different patterns of orbital roof involvement.
| Case Reports|| |
A 54-year-old male presented with proptosis of the right eye that had been slowly progressing over 15 years. This was associated with blurred vision for the 3 months prior to presentation. The patient denied pain or double vision, and there was no history of trauma at any time. The patient had had type 2 diabetes mellitus for more than 20 years. On examination, his best corrected visual acuity in the right eye was count fingers at 3 feet and 20/25 in the left eye, with no relative afferent pupillary defect. Color vision and confrontation visual fields were normal bilaterally. Mild restriction of ocular motility in superior gaze, as well as 4 mm of proptosis and 4 mm of hypoglobus were present. A palpable mass was present above the globe [Figure 1]a. The fundus exam showed severe bilateral nonproliferative diabetic retinopathy, with greater macular edema in the right eye compared to the left eye. Fundus fluorescein angiography revealed evidence of an ischemic macula in the right eye. Macular edema was responsible for his decreased vision and this was managed with laser photocoagulation by the retina service. An orbital computed tomography (CT) scan indicated a large intra-orbital cyst in the superotemporal aspect of the right orbit, which was associated with an irregular bony erosion of the orbital roof and inferior displacement of the globe [Figure 1]b. Magnetic resonance imaging (MRI) of the orbit was not performed.
|Figure 1: (a) A 54-year-old male presented with slowly progressive proptosis in his right eye for more than 15 years. (b) Coronal orbital CT scan demonstrates a large intra-orbital cyst in the superotemporal aspect of the right orbit associated with an irregular bony erosion of the orbital roof and an inferior displacement of the globe. (c) Giant cells surround the clefts created by cholesterol crystals seen on histopathology evaluation of the cyst (H and E, ×10). (d) Six months following removal of the mass there is adequate cosmesis and no evidence of recurrence|
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The patient underwent a right lateral orbitotomy and the entire cyst was removed intact. The cyst was filled with a dark yellowish material. A large defect in the orbital roof (2.5 × 2.0 cm) was noticed intraoperatively; however, the dura over the defect was intact. Histopathology of the specimen showed a benign fibrous-walled cyst containing areas of calcification, birefringent and crystalline foreign particles with giant cell reaction and numerous cholesterol clefts [Figure 1]c. The cyst lacked an epithelial lining. These histopathological findings are consistent with CG. The postoperative course was unremarkable and there is no sign of recurrence at 6 months [Figure 1]d.
A 45-year-old female was referred for further management of progressive proptosis and pressure sensation in her left eye. The proptosis had been present since childhood. She denied having any pain, decreased vision, or diplopia. There was no history of trauma. On examination, her visual acuities were 20/25 in the right eye and 20/20 in the left eye, with no relative afferent pupillary defect. The color vision and visual field test results were normal bilaterally. On examination, there was mild restriction of ocular motility on superior gaze in the left eye, as well as 3 mm of proptosis and hypoglobus and fullness below the central and temporal aspects of the left brow [Figure 2]a. The fullness was bony and not tender or erythematous. The rest of the ocular examination was normal.
|Figure 2: (a) A 45-year-old female presented with progressive proptosis and a pressure sensation in her left eye for many years. (b) A coronal orbital computed tomography scan demonstrates a very large intraosseous cyst involving the frontal bone superotemporally, with evidence of bony erosion. (c) Macroscopic picture of the yellow solid material contained within the removed lesion. (d) Six months following removal of the mass there is marked improvement in cosmesis and in the fullness below the central and temporal aspect of the left brow|
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Orbital CT showed a large intraosseous cyst involving the frontal bone superotemporally and evidence of bony erosion [Figure 2]b. MRI of the orbit was not performed.
The patient underwent a left lateral orbitotomy via the lid crease approach. A large bony cyst filled with yellow material was removed, and curettage of the bone was done to remove the granulomatous tissue and fibrous capsule that were adherent to the bone and the periosteum [Figure 2]c. The histopathological findings were consistent with CG. At 6 months postoperatively, there were no sequelae, and only mild hypoglobus was present on the left side [Figure 2]d.
| Discussion|| |
An osteolytic lesion with a granulomatous reaction to the presence of cholesterol crystals is defined as CG.  A fibrous capsule may also be present in addition to evidence of an old hemorrhage.  A variety of names have been used to describe these lesions, including lipid granuloma of the frontal bone, chronic hematic cyst, and xanthomatosis of the orbit. CG has a male preponderance and usually occurs in young or middle-aged men.  The pathogenesis of CG and the reason it mainly affects the lacrimal region of the frontal bone are currently unknown. Several hypotheses have been proposed. The most widely accepted is that there is the presence of a nonabsorbed hematoma from an episode of mucosal bleeding in the frontal sinus, resulting in the formation of cholesterol crystals and a foreign body chronic inflammatory reaction.  Hemorrhage is thought to be the source of the cholesterol due to the breakdown of blood-derived products.  The adjacent bone resorption is believed to be initiated by prostaglandins that are produced by platelets within the hematoma. 
Orbital imaging studies are very helpful for diagnosing CG. A typical CT scan of a CG shows a lesion that is noncalcifying, with a smooth outline, rounded in shape, isodense with brain, and located in the superolateral bony orbit with an extraconal soft tissue mass, leading to inferior and anterior displacement of the globe.  A CT scan provides an opportunity to evaluate the extension of the intraosseous portion of CG. A sclerotic margin between the mass and the normal diploic spaces is not usually detected on a CT scan obtained with a bone window setting. In addition, postcontrast CT scans show no enhancement of CGs.  The diagnosis of CG is well established with MRI because the lesion emits a signal of high intensity on both T1- and T2-weighted images (due to the presence of hemoglobin breakdown products around the cholesterol crystals) with interspersion of either septations or foci of low signal.  The characteristic signal of high intensity that is detected on all images, reflecting a shortening of the T1-involved tissue and a lengthening of the T2, is caused by the paramagnetic effect of heme iron (Fe3p) in methemoglobin.  The use of a gadolinium contrast dye in the MRI scan does not enhance CG. These orbital imaging findings are in agreement with the histological findings of fibrous tissue containing cholesterol clefts, an inflammatory infiltrate, and chronic hemorrhagic products.
The definitive management of CG is drainage and total removal of granulomatous tissue via an anterior, or occasionally, lateral orbitotomy.  Careful curettage or dissection is essential to prevent recurrence due to residual granulomatous material that adheres to the bone and the orbital periosteum. 
CG is a rare condition, with different patterns of orbital roof involvement. Familiarity with the clinical presentation and the characteristic CT and MRI features enables the clinician to make this diagnosis with reasonable confidence. Treating CG with simple drainage and curettage of granulomatous tissue via an orbitotomy is adequate and recurrences are rare.
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[Figure 1], [Figure 2]