DOI: 10.33962/roneuro-2021-032 Lateral orbitotomy in the management of an intra-orbital lipoma. A case report Mandour Cherkaoui, Ait Lhaj El Houssaine, Khouya Ali Adil, Gazzaz Miloudi, E.L. Mostarchid Brahim Romanian Neurosurgery (2021) XXXV (2): pp. 204-206 DOI: 10.33962/roneuro-2021-032 www.journals.lapub.co.uk/index.php/roneurosurgery Lateral orbitotomy in the management of an intra-orbital lipoma. A case report Mandour Cherkaoui1, Ait Lhaj El Houssaine2, Khouya Ali Adil2, Gazzaz Miloudi3, E.L. Mostarchid Brahim3 1 Department of Neurosurgery, 5th Military Hospital, Guelmim, MOROCCO 2 Department of Ophthalmology, 5th Military Hospital, Guelmim, MOROCCO 3 Department of Neurosurgery, Military Hospital Mohammed V, Rabat, MOROCCO ABSTRACT Introduction: Lipomas are benign subcutaneous mass, but the intra-orbital location is rarely reported in the literature and it can resemble a variety of other orbital lesions. Case report: We describe a 15-year-old girl who presented with left exophthalmia. Orbital magnetic resonance imaging showed an encapsulated intra-conal mass displacing the optic nerve medially, the external right muscle laterally and the globe anteriorly. Excisional biopsy of the mass by lateral orbitotomy approach resolved the exophthalmia, and histology revealed a primary orbital lipoma. Conclusion: The diagnosis of an intra-orbital lipoma is not easy and the surgical approach represents a challenge to achieve a total excision while avoiding complications. INTRODUCTION Lipoma is a benign mesenchymal neoplasm composed of mature adipose tissue surrounded by a fibrous tissue capsule1. The majority is developed in the subcutaneous soft tissue in the neck, shoulder and back, but it is uncommon in the orbital region2. We describe a case of exophthalmia caused by an intra-orbital lipoma and review of the literature. CASE REPORT A 15-year-old Moroccan girl, admitted to our department for treatment of a progressive left exophthalmia for 06 months. There was no history of trauma, visual disturbances, and significant ocular or medical histories. On ocular examination, she had visual acuity of 20/20 in both eyes with a left axile, reducible and non-pulsatile exophthalmia. Orbital Magnetic Resonance Imaging (MRI) revealed an encapsulated intra- conal mass (2.5 x 1,7 x 0,5 cm) in the posterolateral compartment of the left orbit. The mass was displacing the optic nerve medially, the external Keywords exophthalmia, lateral orbitotomy, lipoma, orbital Corresponding author: Mandour Cherkaoui Department of Neurosurgery, 5th Military Hospital, Guelmim, Morocco mandour1978@hotmail.com Copyright and usage. This is an Open Access article, distributed under the terms of the Creative Commons Attribution Non–Commercial No Derivatives License (https://creativecommons .org/licenses/by-nc-nd/4.0/) which permits non- commercial re-use, distribution, and reproduction in any medium, provided the original work is unaltered and is properly cited. The written permission of the Romanian Society of Neurosurgery must be obtained for commercial re-use or in order to create a derivative work. ISSN online 2344-4959 © Romanian Society of Neurosurgery First published June 2021 by London Academic Publishing www.lapub.co.uk http://www.lapub.co.uk/ 205 Lateral orbitotomy in the management of an intra-orbital lipoma right muscle laterally and the globe anteriorly with resultant exophthalmia. Hypointense at T1 and hyperintense at T2 taking the contrast (Figure 1-2). A left lateral orbitotomy approach was utilized with an excisional biopsy (Figure 3-4). Histopathological evaluation revealed well-encapsulated, mature adipose tissue consistent with a primary orbital lipoma. After surgery, exophthalmia had subsided with a normal ocular motility. Figure 1. Post contrast axial T1-weighted MRI showing hyper intense lesion (arrow). Figure 2. Axial T2-weighted MRI showing hyper intense lesion (arrow). Figure 3. Preoperative photograph showing the incision for a left lateral orbitotomy. Figure 4. Intra-operative photograph showing tumor excision. DISCUSSION Lipoma is a benign lobulated tumor composed of mature adipose tissue surrounded by a fibrous tissue capsule. Frequently it is localized subcutaneously around the torso, neck, and proximal limbs3, but in the orbital region is uncommon with the reported incidence of 0.6% in adults and 2.8% in children4. The exact etiology of lipoma formation is unknown, but there are instances following trauma4,5. Also some hypotheses have been mentioned as hypertrophy theory (the growth of the tumor is caused by obesity) and metaplasia theory (the growth of lipoma occurs due to differentiation of mesenchymal cells into lipoblast) 6. Generally, orbital lipoma slow growing and often asymptomatic until large enough to be palpable, visible or cause mass effect. Rarely grows and compresses the optic nerve causing disturbance in visual function7. The radiological appearance of orbital lipoma, on computed tomography the tumor has a distinctive low attenuation with a finely defined border. On MRI it is generally hyperintense on T1-weighted imaging and indistinct to orbital blood on T2-weighted images, hypointense after fat suppression. However, it is not enhanced after contrast images8, but in our case the lesion was hyperintense. Due to the various presentations of lipoma, the diagnosis is not always easy and other orbital masses should be considered in the clinical differential diagnosis, such as dermoid cyst, fibrous histiocytoma, schwannoma and cavernous hemangioma9. The recommended treatment is the surgical excision and it is a challenge because of the complex anatomy of the orbital structures10, 11. In our case, the patient was operated by a lateral orbitotomy with removal of the tumor. The long-term outcome after surgery is seen to be excellent however, recurrence of the tumor may occur due to incomplete excision12. CONCLUSION We present a case of a rare intra-orbital tumor whose surgical approach such as lateral orbitotomy is a real challenge for neurosurgeons. CONSENT Written informed consent was obtained from the patient for publication of this case report and accompanying images. ABBREVIATIONS MRI: Magnetic resonance imaging 206 Mandour Cherkaoui, Ait Lhaj El Houssaine, Khouya Ali Adil et al. AUTHOR’S CONTRIBUTIONS: C M: manuscript writing; A L and A K: manuscript preparation; B E and M G: manuscript analysis. All authors read and approved the final manuscript. ACKNOWLEDGEMENTS This study received no funding CONFLICTS OF INTEREST The authors declare no potential conflict of interest REFERENCES 1. Pranav Shrestha; Gulshan Bahadur Shrestha. Orbital Lipoma as an Uncommon Cause of Unilateral Proptosis: A Case Report. International Medical Case Reports Journal. 2020:13 415–418. 2. Rodiah Rahmawaty Lubis. Giant Preseptal Upper Eyelid LipomaI. A Case Report. EuroMediterranean Biomedical Journal. 2020: 15 (13) ; 58–60. 3. Weiss S. Lipomatous tumours. Monogr Pathol 1996; 38: 207–239. 4. CPT Matthew; Chorost MC ; LTC Vladimir Yakopson, and al. Posttraumatic Encapsulated Orbital Lipoma. Military Medicine. 2020:185, 9/10:e1876. 5. Aust MC, Spies M, Kall S, Joukuszies A, Gohritz A, Vogt P. Lipomas after blunt soft tissue trauma: are they real? Analysis of 31 cases. 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