Acute unilateral vision loss and bilateral cerebral infarction following cosmetic filler injection.

The current case report describes acute unilateral vision loss and bilateral cerebral infarction as devastating complications following cosmetic injection of hyaluronic acid to the nasal bridge in a 34-year-old female. The patient reported the onset of sudden eye pain, headache, and vision loss in her right eye. At the initial visit to the hospital, the patient had no light perception in the right eye. Examinations revealed marked ptosis and complete ophthalmoplegia with no proptosis. At the time of the patient's hospital evaluation, computed tomography, and magnetic resonance imaging were ordered. Few mottled materials (denser than blood) were observed in the cavernous sinus with a density of 106 Hounsfield units (HU), yet no air was depicted in the cavernous sinus. MRI scan revealed multiple areas of bilateral intracranial infarcts. Although cosmetic injection of hyaluronic acid has been documented as a safe procedure, vision loss remains one of the most feared complications.

Involvement of Multiple Trigeminal Nerve Branches in IgG4-Related Orbital Disease.

PURPOSE: To describe the occurrence of multiple trigeminal nerves (TGNs) enlargement in patients with orbital IgG4-related disease. METHODS: Retrospective review of MRI findings and medical records of 6 patients (10 orbits) with orbital IgG4-related disease and enlargement of more than 1 TGN. Orbital biopsies were performed in all cases revealing the typical lymphoplasmacytic infiltrate with significant plasma cell positivity for IgG4 (IgG4+/IgG ratio ≥ 40%). Three experienced neuroradiologists reviewed the MRI sequences using a digital imaging viewer system (Horos, https://horosproject.org/). RESULTS: Bilateral involvement of at least 2 TGNs divisions was detected in all 6 patients. Enlargement of both V1 and V2 nerves was diagnosed in 5 patients, and in 3 cases, all TGN divisions were involved. V2 nerves were the most affected. In this division, all 12 infraorbital nerves were enlarged, followed by lesser palatines (10/83.3%), superior alveolar (10/83.3%), and zygomatic (6/50%). V1 and V3 nerves were less affected albeit 9 (75%) frontal branches (V1), and 50% of the inferior alveolar (V3) nerves were also enlarged. CONCLUSIONS: Widespread involvement of the TGN is an important feature of IgG4-related disease.

Characteristics and management of congenital anophthalmos and microphthalmos at a tertiary eye hospital.

Purpose: The purpose of the study is to evaluate demographic data and outcomes of the management of congenital anophthalmia/microphthalmia. Methods: This retrospective, descriptive, cross-sectional study evaluated patients with congenital anophthalmia/microphthalmia managed from 2004 to 2014 at a tertiary hospital in Saudi Arabia. Data were collected on patient age, gender, cause, orbital status, laterality, systemic comorbidities, ocular evaluation, and management (type of surgery, type of orbital implant, and complications). The main outcome measure was the ability to hold the prosthesis. Results: The study sample was composed of 513 eyes/sockets of 365 patients. Two-hundred and seventeen (59.4%) patients were unilateral cases. Forty-one (8%) sockets were due to congenital anophthalmia and 471 (92%) were due to microphthalmia. There were 73.2% isolated cases and 28.5% with systemic involvement. Systemic involvement was more common in bilateral cases. The most commonly associated conditions were central nervous disorders. One-hundred and nineteen (46.7%) cases had parental consanguinity. Two hundred and eighteen eyes/sockets (163 patients) underwent surgery including conjunctival flap (38; 17.4%), evisceration (38; 17.4%), enucleation (16; 7.3%), or procedures to improve the anophthalmic socket volume (45; 20.6%). Volume enhancing procedures included polymethylmethacrylate orbital implants (26; 57.8%), expanders (11; 24.4%), integrated hydroxyapatite or polyethylene implants (2; 4.4%), and dermis-fat graft (6; 13.3%). In most cases, clinical or surgical management resulted in a successful outcome. Conclusion: Anophthalmia/Microphthalmia was detected in 36.5 patients/year. The majority had isolated microphthalmia. Good outcomes were achieved with clinical or surgical management in the majority of cases.

Recurrent Orbital Inflammation Mimicking Orbital Cellulitis Associated With Orbitopalpebral Venous Lymphatic Malformation.

An 8-year-old boy initially presented with an orbitopalpebral mass diagnosed clinically and radiologically as a low-flow diffuse venous lymphatic malformation involving the left upper eyelid and orbit. Over 8 months of follow up, he had 2 acute episodes of severe orbital inflammation that warranted hospitalization and treatment with intravenous antibiotic, steroids and surgical debulking. After a third surgical excision, the lesion remained clinically stable.

Hyperostosis Following Orbital Exenteration.

PURPOSE: To describe CT scan findings following orbital exenteration in 27 patients and to identify the factors involved in the development of post exenteration hyperostosis. METHODS: Noncomparative case series. The authors reviewed the charts of 27 patients ranging in age from 33 to 99 years, who underwent unilateral exenteration at King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia and at the School of Medicine of Ribeirão Preto, University of São Paulo, Brazil. Data regarding patient demographics, surgical procedure, clinical diagnosis, and preoperative and postoperative CT imaging of the orbits were obtained. The relationship between hyperostosis and postoperative time, gender, age, adjuvant radiotherapy, and cavity coverage was evaluated by multivariate stepwise logistic regression. RESULTS: Seventeen (73.9 %) orbits had postoperative orbital hyperostosis. No soft tissue masses were detected in the affected orbits except in 2 cases with tumor recurrence. The only factor associated with hyperostosis was immediate intraoperative socket rehabilitation (odds ratio = 0.13, 95% confidence interval: 0.01-0.89). There was an 87.0% lower chance of hyperostosis in patients whose socket was covered with musculocutaneous flaps. Sequential CT scans showed that orbital hyperostosis followed a specific pattern. Initially, bone thickening appeared as either uniform or undulating endo-osteal minimal thickening along the roof and then on the lateral and medial walls. More advanced hyperostosis had a laminated/lamellated appearance progressing to homogeneous and diffuse circumferential bone thickening. New bone formation and bone overgrowth were late findings. Hyperostosis extended to involve the adjacent facial bone, more obviously on the maxilla. Some patients had minimal thickening of the adjacent frontal and squamous temporal bone. Over-pneumatization of the paranasal sinuses was evident in all cases of hyperostosis. CONCLUSIONS: Development of hyperostosis following exenteration is not rare. Radiologists and surgeons should be aware of the need to monitor the orbital healing process closely to avoid misdiagnoses of tumor recurrence/radionecrosis or infection. Obliteration of the orbital cavity with musculocutaneous flaps significantly reduces the chances of bone hyperostosis.

Central Retinal Vein Occlusion in a Childhood Optic Nerve Tumour.

The authors describe the first paediatric patient with an aggressive optic nerve tumour of uncertain histology causing a central retinal vein occlusion, retinochoroidal collaterals, arteriovenous anastomoses, and peripheral retinal non-perfusion. He first presented with pale optic nerve head, followed by development of optic disc oedema a year later. Certain optic nerve tumours can present with central retinal vein occlusion in the paediatric age group.

An advanced case of pediatric ciliary body medulloepithelioma with detailed literature review.

INTRODUCTION AND IMPORTANCE: Medulloepithelioma is the second most common primary intraocular malignant tumor in children but is often diagnosed late, which worsens the prognosis. CASE PRESENTATION: We are reporting a 6-year-old boy presenting with a ciliary body (CB) teratoid malignant medulloepithelioma (TMM), which was missed at the initial presentation. We added our case to the 97 previously reported cases in our literature review that were confirmed by cytological or histopathological examination. DISCUSSION: Medulloepithelioma has a wide age range at presentation with a mean of 5.3 ± 4.1 years, and slight male predominance (M: F ratio of 1.15). Clinically, the main symptoms/ signs are reduced visual acuity, lens changes, or a pupil "mass." Almost all reported medulloepitheliomas were unilateral (98 %). Histopathologically, non-teratoid malignant medulloepithelioma (NTMM) (35.7 %) and TMM (34.5 %) were the commonest. Enucleation was the main treatment modality because of the large tumor size of 72.7 %. A combination of chemotherapy and/or radiotherapy was used in 15.1 % and brachytherapy for small lesions in 14.1 %. Orbital exenteration was needed in 3 cases because of orbital invasion. CONCLUSION: A CB medulloepithelioma tumor can be easily missed, diagnosed late, with less chance for globe salvaging. The malignant types are more common and may result in orbital invasion, requiring even more extensive surgery. Therefore, when facing a child with lens changes, a pupil "mass," or raised intraocular pressure, pediatricians and general ophthalmologists must have an earlier suspicion and be aware of this rare entity to improve outcomes and reduce loss of vision or other disease-related morbidity.

Optic Nerve Avulsion: Pattern and Etiologies at a Tertiary Eye Care Center in Saudi Arabia: An 8-Year Retrospective Study.

Purpose: Optic nerve avulsion (ONA) is a rare but serious presentation of ocular trauma. This study investigates the presenting characteristics and etiologies of all cases of ONA over an 8-year-period at a tertiary eye care center in the Middle East. Methods: The medical records of patients diagnosed with ONA at an Ophthalmic Emergency Department between November 2014 and November 2022 were analyzed in this retrospective cohort study. Data were collected on patient age, sex, affected eye, cause of injury and imaging studies. The best-corrected visual acuity (BCVA) at presentation and at the last follow-up visit, and the duration of follow-up were documented. Results: The study sample was comprised of 44 eyes of 43 patients with ONA with median age of 16.5 (9.3-26.8) years ranging from 2 years old to 70 years old. There were (35;79.5%) males and (9; 20.5%) females. Most cases presented with an affected left eye (27; 61.4%) followed by the right eye (16; 36.4%) and only one patient (2.3%) had bilateral ONA. The most common cause of trauma resulting in ONA was a metallic object (8;18.2%). This study demonstrates the value of multi-sequence Magnetic resonance imaging (MRI) in the setting of unexplained vision loss when other modalities are inadequate or inconclusive. Conclusion: Ophthalmic morbidity resulting from ONA can be devastating. Metallic object injuries were the most prevalent cause of ONA. The presence of associated media opacities challenges the initial diagnosis of ONA. In the vast majority of cases, the vision ended as no light perception (NLP), indicating permanent vision impairment.

Visual loss in orbitofacial neurofibromatosis type 1.

PURPOSE: On occasion, neurofibromas in neurofibromatosis type 1 may be present on the lid, brow, or face of an infant or child, a circumstance commonly referred to as "orbitofacial neurofibromatosis" (OFNF). The present study evaluates the causes and extent of visual loss in a group of patients with OFNF. DESIGN: Case series. PARTICIPANTS: Fifty-five patients with OFNF. METHODS: Retrospective medical record review and reexamination of selected patients from one institution. MAIN OUTCOME MEASURES: Visual acuity and identification of underlying cause of reduced vision. RESULTS: Fifty patients with unilateral OFNF (23 male, 27 female, aged 4-48 years at last visit) and 5 patients with bilateral OFNF (2 male, 3 female, aged 15-43 years) had adequate information available to assess afferent visual functioning. Nine patients (4 male, 5 female, aged 4-28 years) had optic pathway glioma (OPG) in addition to OFNF. Patients were followed as long as 27 years (mean 8.4 years). Thirty-nine patients (71% of total) had visual acuity of ≤20/60 on the side of OFNF involvement (or the side of worse OFNF involvement in patients with bilateral disease). One or more causes of amblyopia were present in 29 of these patients, 19 patients had organic disease of the eye (e.g., glaucoma or retinal detachment) or the afferent system (e.g., OPG), and 12 patients had correctable refractive errors. CONCLUSIONS: Visual loss in this OFNF cohort was common, typically profound, and usually multifactorial. Some causes of visual loss (including congenital glaucoma with buphthalmos and retinal detachment, disconjugate gaze due in part to distorted skull development causing strabismic amblyopia, and OPG) were difficult to treat adequately and tended to cause progressive, profound visual loss. Therefore, careful observation should be made during the period of visual immaturity for possible causes of amblyopia that might be treatable, such as refractive changes, occlusion of the visual axis, or congenital glaucoma. As affected individuals get older, physicians must be vigilant for the progression of optic nerve disease due to glaucoma or OPG and to the possibility that vision might be improved by refraction.

Acute dacryocystitis retention: a case report and literature review.

Acute dacryocystitis retention (ADR) is an unusual entity that contributes to an incorrect diagnosis and treatment. We describe a case of acute dacryocystitis retention occurring in a 61-year-old diabetic male who presented with severe pain, swelling, and inflammatory signs above the left medial canthal ligament tendon. He had no previous history of epiphora. Computed tomography scan indicated acute dacryocystitis. Clinical treatment resulted in complete resolution of the condition. Syringing one month after the acute episode indicated a patent lacrimal excretory system. The temporary obstruction that evolved to an acute dacryocystitis retention was probably secondary to nasal alteration or supposed dacryoliths. Timely, conservative clinical treatment can lead to complete resolution of acute dacryocystitis retention with no further treatments.

Orbital and periorbital migration of silicone oil associated with emphysema development after retinal detachment repair - Case report and literature review.

PURPOSE: To report a very rare case of silicone oil (SO) migration and emphysema development in the orbit and periorbital tissue, including the lids and subconjunctival space, after a fourth pars plana vitrectomy (PPV) for retinal detachment (RD) treatment. OBSERVATIONS: A 53-year-old woman with a recurrent rhegmatogenous RD in the right eye underwent a fourth PPV under local anesthesia and 23-gauge vitrectomy with fluid-air exchange and SO injection. Localized choroidal detachment occurred during fluid-air exchange near the end of the surgery. High-pressure infusion of air was used as a temporary control measure prior to SO injection. In the early postoperative period, the patient developed hemifacial and periorbital swelling and the air trapped in the upper lid was associated with lid ptosis and conjunctival chemosis. The emphysema resolved with clinical management, and the mechanical ptosis subsided after partial SO removal from the lid. CONCLUSIONS AND IMPORTANCE: The SO migration and emphysema in our case were presumably related to the multiple previous sclerotomies. Periorbital emphysema can show spontaneous resolution, but the migrated SO requires surgical management.

Invasive sino-orbital aspergillosis with brain invasion in an immunocompetent pregnant patient.

PURPOSE: Invasive Fungal Sinusitis (IFS) is a potentially life-threatening condition that can progress rapidly to the orbit and the brain, especially if it goes on undetected for a long period. We report a case of a 28-year-old pregnant woman in her second trimester with sino-orbital A spergillosis and subsequent brain involvement who tragically developed deterioration of her neurological status and a spontaneous abortion. OBSERVATIONS: The patient presented to the ophthalmology emergency department, King Khaled Eye Specialist Hospital, Riyadh, complaining of left upper eyelid fullness with a palpable eyelid mass and chronic relapsing remitting dull pain for 4 months. Clinical examination was significant for reduced colour vision in the left eye, limited left supraduction, left upper eyelid firm palpable mass, inferior dystopia and proptosis of 4 mm. Magnetic Resonance Imaging (MRI) done without contrast-enhancement due to her pregnancy revealed aggressive infiltrative sinonasal, nasal septum, cribriform plate, orbital, intracranial infiltration with extensive brain edema and midline falcine herniation patterns. Endoscopic endonasal biopsy of the lesions showed septate hyphae branching at acute angles, suggestive of A spergillosis. Her neurological status deteriorated with a spontaneous abortion during admission. CONCLUSIONS AND IMPORTANCE: This case demonstrates that IFS could present only with proptosis, eyelid fullness, chronic pain without external inflammatory signs and should be considered in such presentation even in immunocompetent patients. Early detection and management are crucial. Whether pregnancy presents a relative immune susceptibility to IFS is an issue that needs further in-depth investigation.

Lacrimo-auriculo-dento-digital syndrome: A case report and literature review.

We report a healthy 18-year-old male Saudi with bilateral agenesis of the lacrimal puncta and canaliculi associated with large dacryocystocele on the right side without tearing or inflammation, detected in conjunction with other characteristic features of lacrimo-auriculo-dento-digital dysplasia syndrome. Computed tomography scan indicated that dacryocystoceles were bilateral and asymmetrical, with large dimensions at the right side and associated to a right side maxillary sinus mucocele. The right dacryocystocele was surgically removed, and the histology indicated characteristics of the lacrimal sac. The liquid content of the dacryocystocele was negative for microbes. The atypical mucocele in the maxillary sinus disappeared after dacryocystocele removal probably, due to recovery of sinus drainage.

Isolated traumatic optic nerve avulsion in a boy who suffered a horse kick.

We report a case with traumatic avulsion of optic nerve caused by a horse kick in a child that caused loss of vision. Optic nerve avulsion is a rare injury usually associated with maxillofacial structures. Our patient had no light perception in the left eye. The left pupil was dilated and unreactive to light. The left globe was intact. A non-contrast axial computed tomography scan of the orbit demonstrated a widened and altered nerve globe junction with periorbital soft tissue edema. At six month following the injury, subsequent magnetic resonance imaging of the orbit showed that the preseptal soft tissue thickening dispersed spontaneously with total avulsion of the optic nerve and variable severity of surrounding hemorrhage. The patient did not develop phthisis bulbi during three years of follow up. Traumatic optic nerve avulsion presents with a dramatic clinical picture, and can lead to the development of severe visual loss.

Adult presentation of retinoblastoma in Saudi patient.

To describe an unusual case of retinoblastoma in adult Saudi. A 21-year-old Saudi male developed acute unilateral visual loss due to a large intraocular lesion in his left eye. Within five days of presentation, the tumor enlarged rapidly causing angle closure glaucoma and orbital cellulitis like picture. The patient underwent enucleation and the histopathology specimen confirmed the presence of an undifferentiated type tumor cell that was consistent with retinoblastoma with choroidal and optic nerve invasion. Retinoblastoma should be considered in the differential diagnosis of an intraocular mass in adults. To the best of our knowledge, this is the first reported case of an adult presentation of retinoblastoma in Saudi patient.

Orbital solitary fibrous tumors: a multi-centered histopathological and immunohistochemical analysis with radiological description.

BACKGROUND: Solitary fibrous tumors (SFT), formerly called hemangiopericytoma, are rare tumors derived from mesenchymal cells originally described in the pleura, but these tumors may affect extraserosal tissues including the lacrimal gland and orbit. OBJECTIVE: Conduct a multi-centered clinical, radiological and histopathological analysis of 17 orbital SFT cases. DESIGN: A retrospective case series. SETTING: Three eye centers in two countries. PATIENTS AND METHODS: The data collected from the charts of 17 adult patients presenting with tissue diagnosis of orbital hemangiopericytoma or SFT from January 2003 to December 2018 included demographics, clinical imaging and histopathological information including immunohistochemical (IHC) characteristics. MAIN OUTCOME MEASURES: The demographic characteristics, clinical presentation, and histopathological patterns or variants of SFT were analyzed. SAMPLE SIZE: 17 adult patients. RESULTS: Mean age was 45 years (range 23-80 years). Male to female ratio was 3:1. The right eye was affected in 12 (70.5%) patients. Commonest presentation was proptosis in 13/17 (76% of patients). Other symptoms were impaired motility (29%) and ptosis (11%). Lesions mostly affected the medial orbit (35%), then orbital apex in 11%. The histopathological classic pattern-less variant was the commonest. One case with aggressive behavior, multiple recurrences and atypical features was encountered. Immunohistochemical (IHC) markers used included CD34 expression in all cases, Bcl-2 expression in 10/11, CD99 in 9/9 and Vimentin in 4/4. STAT6 was used in 2 cases. CONCLUSIONS: SFTs are rare tumors affecting the orbit in both genders equally in their mid-forties, but showed male predominance in our analysis with a predominant classic histopathological pattern. Tissue diagnosis is essential and requires IHC studies for confirmation. LIMITATIONS: Sample size is relatively small owing to the rarity of this tumor in the orbit. CONFLICT OF INTEREST: None.

Genetic profiling of rhabdomyosarcoma with clinicopathological and radiological correlation.

OBJECTIVE: Orbital Rhabdomyosarcoma is a highly malignant tumor predominantly affecting children. Our study adds more understanding of this tumor to ophthalmologists from the clinicopathological, radiological and genetic aspects. DESIGN: A retrospective clinicopathological and radiological study of ocular rhabdomyosarcoma with genetic profiling. PARTICIPANTS: All the cases with confirmed tissue diagnosis of orbital rhabdomyosarcoma presenting at a tertiary eye hospital in Riyadh, Saudi Arabia during the period 1985-2015. METHODS: Charts and histological slides of 26 patients were reviewed. DNA was extracted from paraffin-embedded biopsies and genotyping was performed to detect chromosomal abnormalities and Copy-number variations regions. RESULTS: 18 males and 8 females were included with a mean age at presentation of 6.9 years (SD of 4.4). Proptosis and globe displacement were the commonest clinical presentations. Embryonal histopathological type was the commonest (73.1%) with superior orbital involvement (p = 0.024). Using magnetic resonance imaging, the embryonal type showed higher Apparent diffusion coefficient (ADC) value compared to the alveolar type (p = 0.98). Genetic profiling showed Copy-number gain in regions spanning PAX3, DDIT3, Gli, Wnt6 genes. DICER1 gene implication was found in 9 sporadic cases. CONCLUSION: Rhabdomyosarcoma is rare and occurs with a mean age of 7 years, predominantly among males. The commonest embryonal type is significantly correlated with superior orbital involvement. Radiologically, it shows an ADC of 0.67-0.09 × 10-3mm2/s. (p = 0.98). The gain in PAX3, DDIT3, Gli1, Wnt6 genes is a new finding while the DICER1 gene implication in the absence of familial hereditary carcinoma is another interesting finding.

Tungiasis infestation of dermis fat graft in an anophthalmic socket.

A patient with an anophthalmic socket with a dermis-fat graft (DFG) developed inflammation and a foul odour in the right socket. The DFG was surgically removed and Tungiasis infestation was detected. This is the first case to report Tungiasis infestation in a DFG in an anophthalmic socket.

ACVR1C/SMAD2 signaling promotes invasion and growth in retinoblastoma.

Retinoblastoma is the most common intraocular cancer in children. While the primary tumor can often be treated by local or systemic chemotherapy, metastatic dissemination is generally resistant to therapy and remains a leading cause of pediatric cancer death in much of the world. In order to identify new therapeutic targets in aggressive tumors, we sequenced RNA transcripts in five snap frozen retinoblastomas which invaded the optic nerve and five which did not. A three-fold increase was noted in mRNA levels of ACVR1C/ALK7, a type I receptor of the TGF-ß family, in invasive retinoblastomas, while downregulation of DACT2 and LEFTY2, negative modulators of the ACVR1C signaling, was observed in most invasive tumors. A two- to three-fold increase in ACVR1C mRNA was also found in invasive WERI Rb1 and Y79 cells as compared to non-invasive cells in vitro. Transcripts of ACVR1C receptor and its ligands (Nodal, Activin A/B, and GDF3) were expressed in six retinoblastoma lines, and evidence of downstream SMAD2 signaling was present in all these lines. Pharmacological inhibition of ACVR1C signaling using SB505124, or genetic downregulation of the receptor using shRNA potently suppressed invasion, growth, survival, and reduced the protein levels of the mesenchymal markers ZEB1 and Snail. The inhibitory effects on invasion, growth, and proliferation were recapitulated by knocking down SMAD2, but not SMAD3. Finally, in an orthotopic zebrafish model of retinoblastoma, a 55% decrease in tumor spread was noted (p = 0.0026) when larvae were treated with 3 µM of SB505124, as compared to DMSO. Similarly, knockdown of ACVR1C in injected tumor cells using shRNA also resulted in a 54% reduction in tumor dissemination in the zebrafish eye as compared to scrambled shRNA control (p = 0.0005). Our data support a role for the ACVR1C/SMAD2 pathway in promoting invasion and growth of retinoblastoma.

Characterization of diffuse orbital mass using Apparent diffusion coefficient in 3-tesla MRI.

PURPOSE: To evaluate if the apparent diffusion coefficient (ADC) value in diffusion-weighted magnetic resonance imaging (DW-MRI) improves the diagnostic accuracy of diffuse orbital masses. MATERIALS AND METHODS: ADC DW-MRI was used to evaluate cases of diffuse orbital masses at our institution from 2000 to 2015. Lesions were grouped according to histopathologic diagnosis as, benign, pre-malignant and malignant. Lymphoproliferative lesions were further subgrouped as lymphoma or other lymphoproliferative lesions. The validity of the ADC value for the diffuse orbital mass was compared between groups. The area under curve (AUC) was also calculated. RESULTS: Thirty-nine cases of diffuse orbital masses were evaluated. The median ADC was 0.58 (25% quartile 0.48; minimum: 0.45; maximum: 1.72 × 10(-3)) for the malignant tumors and 1.19 (25% quartile 0.7; minimum: 0.5; maximum: 1.95 × 10(-3) mm(2) s(-1)) for benign lesions. This difference in ADC between lesions was statistically significant (Mann Whitney U test P < 0.001). The median ADC was 0.51 (25% quartile 0.48) for lymphomas and 0.9 (25% quartile 0.7) for other lymphoproliferative lesions. This difference in ADC was statistically significant (Mann Whitney U test P = 0.02). An ADC value of 0.8 × 10(-3) mm(2) s(-1) was noted as the ideal threshold value for differentiating malignant from benign diffuse orbital masses. The validity of ADC in predicting a malignant or benign diffuse orbital mass had a sensitivity of 87%, specificity of 67% and accuracy of 88%. CONCLUSION: ADC is a promising imaging metric to characterize malignant and benign diffuse orbital masses and to distinguish lymphomas from other non-lymphoproliferative lesions.