Pott luck.

A 10-year-old boy presented with headache, fever, left-sided ptosis, and right-sided forehead soft tissue swelling. There was no recent history of trauma or infection. The patient had a large, fluctuant mass on the right side of his forehead, upgaze restriction, left-sided ptosis, and bilateral optic disk edema. Magnetic resonance imaging of the brain showed a frontal bone extradural fluid collection superficial to the superior sagittal sinus in keeping with an epidural abscess. There were multiple venous thromboses and thickening and enhancement of the dura, compatible with meningitis. There was right sphenoid sinusitis. This patient had Potts puffy tumor, a rare diagnosis associated with a forehead swelling from frontal bone osteomyelitis and subperiosteal abscess. It is seen in the pediatric population in association with sinusitis or trauma. Antibiotics, anticoagulation, and acetazolamide were initiated, and the epidural abscess was evacuated. The symptoms and signs resolved with treatment.

Cyclin D1 Expression and Molecular Genetic Findings in Periocular Histiocytoses and Neoplasms of Macrophage-Dendritic Cell Lineage.

PURPOSE: Frequent activating mutations in the mitogen-activated protein kinase (MAPK) pathway genes have been identified in histiocytoses. MAPK signaling consistently upregulates cyclin D1. The goal of this study was to determine whether cyclin D1 expression by immunohistochemistry is a useful diagnostic marker for periocular histiocytoses and to further characterize their genetic basis. DESIGN: Retrospective observational case series. METHODS: Pathology records were searched for all patients with histiocytoses diagnosed between 1995 and 2020. Eleven histiocyte-rich inflammatory lesions and 10 xanthelasma served as controls. Cyclin D1 immunohistochemistry was performed on all tissues. A subset of histiocytoses was evaluated by next-generation sequencing (NGS) and droplet digital PCR (ddPCR). RESULTS: There were 36 patients, 15 males (42%) and 21 females (58%), with histiocytoses: 9 juvenile xanthogranuloma (25%), 8 adult-onset asthma and periocular xanthogranuloma (22%), 7 Langerhans cell histiocytosis (19%), 5 Rosai-Dorfman disease (14%), 5 xanthogranuloma-not otherwise specified (14%), 1 Erdheim-Chester disease (3%), and 1 histiocytic sarcoma (3%). Moderate to strong nuclear cyclin D1 expression was present in ≥50% of lesional cells in histiocytoses (23/36, 64%), significantly more when compared to histiocyte-rich inflammatory lesions (0/11, 0%, P<.001) and xanthelasma (0/10, 0%, P<.001). Cyclin D1 was expressed in <10% of lesional cells in all 11 histiocyte-rich inflammatory lesions (P<.001) and all 10 xanthelasma lesions (P<.001). MAPK pathway gene mutations were detected in 12 of 14 (86%) histiocytoses successfully assayed by NGS and/or ddPCR. CONCLUSIONS: Our study confirms that the cyclin D1 immunohistochemical stain is a useful diagnostic marker for periocular histiocytoses, correlating with underlying mutations in MAPK pathway genes.

Double-hit and triple-hit high-grade B-cell lymphoma of the ocular adnexa.

High-grade B-cell lymphoma (HGBL) with c-MYC and BCL2 and/or BCL6 rearrangements, also known as a double-hit and triple-hit lymphoma, is an aggressive non-Hodgkin lymphoma affecting older adults. After formal recognition of this entity in the 2017 revision of the World Health Organization Classification of lymphoid neoplasms, only two well-documented cases of triple-hit lymphoma of the orbit appear in the literature. Herein, we describe a 70-year-old man with progressive diplopia, ophthalmoplegia, and rapidly enlarging temporal mass. Biopsy revealed a tumor morphologically consistent with HGBL, coexpressing CD20, CD10, BCL6, BCL2, and c-MYC on immunohistochemical analysis. Fluorescence in-situ hybridization showed rearrangements in c-MYC and BCL-2 genes, confirming double-hit HGBL. Systemic workup revealed Ann Arbor stage IV disease. This report reviews the existing literature on ocular adnexal double-hit and triple-hit lymphoma and provides an update on the diagnostic ancillary studies, prognostic implications, and latest management for this aggressive hematolymphoid malignancy.

Ocular adnexal lymphoma: A single-institution retrospective study.

PURPOSE: To characterize demographic, clinical, and histopathologic features of ocular adnexal lymphoma (OAL) at a single institution. METHODS: Retrospective review of all patients with pathologic diagnosis of OAL between 2015 and 2020. RESULTS: There were 133 patients with OAL, with a median age of 65 years (range 23-97) and a slight female predominance (male: female = 1:1.46), (n = 79, 59%). The majority of tumors were non-Hodgkin B-cell lymphomas (n = 131, 99%), most frequently Extranodal Marginal Zone B-Cell Lymphoma (EMZL, n = 93, 70%), followed by follicular lymphoma (n = 21, 16%), chronic lymphocytic leukemia/small lymphocytic lymphoma (n = 7, 5%), diffuse large B-cell lymphoma (n = 5, 4%), and mantle cell lymphoma (n = 5, 4%). The most frequently involved sites included the orbit (n = 85, 64%) and conjunctiva (n = 43, 32%). Information was available on oncologic staging in 78 (59%), treatment in 82 (62%), and follow-up in 75 (56%) patients. By the Ann-Arbor classification system, patients were classified as IE (54/78, 69%), IIE (9/78, 12%), IIIE (6/78, 8%), and IVE (9/78, 12%). The most common treatments included external beam radiotherapy (standard and ultra-low-dose) (48/82, 59%), biologics (22/82, 27%), and surgical excision with cryotherapy (14/82, 17%) (some patients had >1 therapy). Median follow-up time was 24 months (range 0-221 months). Recurrence was observed in 13% (10/75) with a median time to recurrence of 60 months (95% confidence interval 47-73 months). Excision with cryotherapy as a sole treatment modality was associated with earlier recurrence (P = 0.003). CONCLUSION: In this largest single-center study of OAL, we found that most OAL were Ann-Arbor Stage IE EMZL, occurring in older patients with a female predominance. Early recurrence was noted in tumors treated with excision and cryotherapy alone.

Ocular adnexal metastases from renal cell carcinoma: An update and comprehensive literature review.

PURPOSE: The purpose of this study was to review the clinical presentation, systemic work-up, and outcomes of all previously reported ocular adnexal (OA) metastases from renal cell carcinoma (RCC). METHODS: This was a literature review. PubMed and Google Scholar databases were searched for all well-documented cases of OA metastases from RCC. RESULTS: Final analysis identified 44 patients with either biopsy-confirmed (41/44, 93%) or treatment response-documented (3/44, 6%) OA metastases from RCC. Thirty-four (77%) patients were male. The median age was 60 years (mean: 60, range: 22-87 years). The most common presenting signs were proptosis (19/44, 43%) and OA mass (14/44, 32%). Metastases most frequently involved the orbital bones (10/44, 23%) and adjacent extraconal fat, extending from the sinonasal tract in 7/10 (70%) of these cases. OA metastases were initial manifestation of RCC in 18/44 (41%) patients. At the time of primary tumor diagnosis, 22 of 30 (73%) patients had American Joint Committee on Cancer Stage IV disease with metastases to 2 or more sites in 13 (57%) patients. Seventeen of 42 (40%) patients underwent local therapy only, which most commonly included excision/exenteration with margin control (10/17, 59%). Twenty-five of 42 (60%) patients had systemic therapy, which included biologic agents and chemotherapy. The absolute 5-year survival rate was 66% with significantly improved survival in patients reported after 2006 (92% vs. 42%, P = 0.04) and in those with isolated OA metastases (100% vs. 27%, P = 0.02) at 30 months. CONCLUSION: Although RCC metastases to OA occur in a setting of advanced disease, the recent advances in diagnostic modalities and targeted therapies resulted in improved survival.

Escaping from the hunt.

A 69-year-old woman presented with chronic, painful, progressive binocular diplopia. Examination showed deficits in multiple sequential cranial nerves (II, III, IV, V1,2,3, and VI). She was initially diagnosed with Tolosa-Hunt syndrome and had a partial response to systemic corticosteroids. Skull base biopsy eventually showed poorly differentiated carcinoma consistent with perineural spread of squamous cell carcinoma.

Ocular adnexal manifestations of neuroendocrine neoplasms: a case report and a major review.

PURPOSE: To describe a patient with orbital neuroendocrine neoplasm (NEN)/carcinoid tumor and to review the clinical presentation, systemic work-up, histopathologic features, and outcome of all previously reported ocular adnexal (OA) NENs. METHODS: A systematic literature review. PubMed/MEDLINE and Google Scholar databases were searched for all well-documented cases of OA NENs. RESULTS: Final analysis yielded 94 patients with OA NENs, 50 females (53%) and 44 (47%) males with an average age of 63 years (range 14-86). Of 91 patients with known information, the most common presenting signs were proptosis (56/91, 61%) and visual disturbances (42/91, 47%), induced by a mass most commonly associated with an extraocular muscle (49/63, 78%). The majority of tumors (88/94, 94%) were metastases, most commonly from the gastrointestinal tract (52/88, 59%). OA NEN metastasis presented following detection of primary tumor in 73/94 (78%) patients (median time to metastasis 36 months, range 0-288 months) and as an initial manifestation of disease in 15/94 (16%) patients (median time to primary detection 18 months, range 1-108 months). Systemic work-up included extra-OA NEN biopsy (37/54, 69%), multimodal imaging (42/54, 78%), and other laboratory studies (32/54, 59%). Resection with or without adjuvant chemotherapy, radiotherapy, and biologics was the most common intervention for OA NENs (36/82, 44%). Of 67 patients with available follow-up, the median survival was 108 months (95% CI 55-161 months) and the absolute 5-year survival rate was 68%. CONCLUSIONS: OA NENs are almost exclusively metastases and can precede detection of primary tumor by many months, requiring appropriate diagnostic work-up.

Perioperative Prophylactic Antibiotics in 1,250 Orbital Surgeries.

PURPOSE: Intravenous antibiotic prophylaxis is used for many clean-contaminated surgeries or clean surgeries with an implant, but its value for clean orbital surgery has not been determined. This study investigated infection risks and adverse effects related to antibiotics in patients undergoing orbital surgery. METHODS: A prospective, nonrandomized comparative case series of all patients undergoing orbital surgery with participating surgeons between October 1, 2013, and March 1, 2015. Types of surgery, antibiotic regimens, corticosteroid use, antibiotic side effects, and surgical site infections (SSIs) were entered into an electronic database and subsequently analyzed. Cases in which patients received postoperative oral antibiotics were analyzed separately. RESULTS: Of 1,250 consecutive orbital surgeries, 1,225 met inclusion criteria. A total of 1208 patients were included in the primary analysis: 603 received no antibiotic prophylaxis (group A), and 605 received a single dose of intravenous antibiotic (group B). Five patients (0.42%) developed an SSI, 3 in group A and 2 in group B. The difference in SSI rates was not statistically significant between the 2 groups (p = 0.66). Antibiotic prophylaxis, alloplastic implants, paranasal sinus entry, and corticosteroid use were not associated with differences in SSI rates. All SSIs resolved on a single course of oral antibiotics; an implant was removed in 1 case. There were no complications associated with a single dose of intravenous prophylaxis. However, 12% of 17 patients (group C) who received 1 week of oral postoperative prophylactic antibiotics developed antibiotic-related complications (diarrhea, renal injury), yielding a number needed to harm of 8.5. CONCLUSIONS: In this large series, antibiotic prophylaxis does not appear to have reduced the already low incidence of SSI following orbital surgery. Given the detriments of systemic antibiotics, the rarity of infections related to orbital surgery, and the efficacy of treating such infections should they occur, patients undergoing orbital surgery should be educated to the early symptoms of postoperative infection and followed closely, but do not routinely require perioperative antibiotics.

Hide and seek.

A 51-year-old woman with a previous history of rheumatoid arthritis experienced painless progressive visual loss in the left eye for 3 weeks. Fundus examination revealed optic disk pallor in her left eye. Magnetic resonance imaging of the brain and orbits showed enhancement of the pachymeninges and hypersignal at the left optic nerve. Meningeal biopsy was performed. Immunohistochemical staining for IgG4 revealed several IgG4-positive plasma cells, which in some areas reached the number of 50 cells/high-power field. In this case, the clinical and histopathological features of the patient met diagnostic criteria for rheumatoid arthritis and IgG4-related disease, respectively. Rheumatoid arthritis sometimes occurs with abundant IgG4 plasma cells and fulfills the histological diagnostic criteria for IgG4-related disease. This case demonstrates that overlapping features of IgG4-RD and rheumatoid arthritis may present in a single patient.

A Comparison of Endonasal Dacryocystorhinostomy and External Dacryocystorhinostomy: A Report by the American Academy of Ophthalmology.

PURPOSE: To assess the efficacy of endonasal dacryocystorhinostomy (DCR) compared with external DCR. METHODS: A literature search was conducted in the PubMed database in March 2016 and updated in October 2017 and February 2019. The search strategy was designed to update the first Ophthalmic Technology Assessment on endonasal DCR from 2001 by identifying new peer-reviewed human studies reported since 2000 in the English language that compare results of endonasal DCR with those of external DCR. The searches yielded 169 articles. Of these, 13 met the inclusion criteria and were assigned a level of evidence rating. RESULTS: Six of the 13 studies included in this assessment were rated level II and 7 were rated level III. Three of the 13 studies drew conclusions based on statistically significant results, but all of these were level III evidence. Two of these significant studies demonstrated lesser efficacy of endonasal laser DCR (63%-64%) compared with external DCR (94%; P = 0.0002, 0.024). The third study reported that nonlaser endonasal DCR was superior to external DCR (84% vs. 70%; P = 0.03). The remainder of the studies did not find statistically significant differences in success rates between the 2 techniques. CONCLUSIONS: Limited data suggest that laser endonasal DCR may be less effective than external DCR. Existing data are inadequate to draw conclusions about whether endonasal DCR is superior to, equivalent to, or inferior to the gold standard external DCR.

INI1/SMARCB1-Deficient Carcinoma (Rhabdoid Tumor) of the Lacrimal Gland.

Integrase interactor 1 (INI1) is a tumor suppressor gene that is ubiquitously expressed in all nucleated cells. The loss of INI1 protein activity was first demonstrated in aggressive pediatric tumors, including atypical teratoid/rhabdoid (AT/RT) tumor of the central nervous system and malignant rhabdoid tumor of the kidney. Subsequently, INI1 deficiency was discovered in other pediatric and some adult neoplasms. The spectrum of INI1-negative tumors includes a wide variety of neoplasms that occur over a wide age range, are variably aggressive, and have a variable rhabdoid component on histopathologic evaluation. In this report, the authors describe a 27-year-old gravid woman with INI1-deficient carcinoma of the lacrimal gland, previously not described in this location.

Balloon Dacryoplasty for Congenital Nasolacrimal Duct Obstruction: A Report by the American Academy of Ophthalmology.

PURPOSE: To identify the efficacy and adverse event rates of balloon dacryoplasty in cases of congenital nasolacrimal duct obstruction in children who fail to respond to an initial nasolacrimal duct probing. METHODS: A literature search was last performed in September 2017 in the PubMed database to identify all reports of balloon dacryoplasty. All searches up to and including the last search were limited to the English language, and they yielded 104 articles that were assessed for relevancy. Thirty-six articles were selected for full review, and 8 of these were selected for inclusion in this assessment and assigned a quality of evidence rating by the panel methodologist. RESULTS: Three of the 8 studies included in this assessment were rated level II, and 5 were rated level III. Success rates varied from 75% to 100%. Only 2 complications were identified, and these were cases of self-limited postoperative emesis. The 2 studies that compared balloon dacryoplasty with lacrimal stenting reported that outcomes were comparable between the 2 techniques. CONCLUSIONS: Although level I evidence was not available, the studies that were uncovered in the literature review indicate that balloon dacryoplasty is a safe, effective procedure to address congenital nasolacrimal duct obstruction that persists after standard probings. The outcomes of this intervention are similar to those of lacrimal stenting, and the absence of an implanted stent theoretically reduces the risk of complications.

Chemodenervation for the Treatment of Facial Dystonia: A Report by the American Academy of Ophthalmology.

PURPOSE: To review the medical literature on the outcomes and complications of various Food and Drug Administration-approved botulinum toxins for benign essential blepharospasm (BEB) and hemifacial spasm (HFS). METHODS: Literature searches were last conducted in February 2017 in PubMed for articles published in English and in the Cochrane Library database without language limitations; studies published before 2000 were excluded. The combined searches yielded 127 citations. Of these, 13 articles were deemed appropriate for inclusion in this assessment, and the panel methodologist assigned ratings to them according to the level of evidence. RESULTS: A combined total of 1523 patients (1143 with BEB and 380 with HFS) were included in the 13 studies. Five studies provided level I evidence, 2 studies provided level II evidence, and 6 studies provided level III evidence. Pretarsal injections were more efficacious than preseptal injections (96% vs. 86%, respectively). Pretarsal injections also resulted in a higher response rate on clinical scales (P < 0.05) and a longer duration of maximum response for both HFS and BEB. Patients with HFS require lower overall doses of onabotulinumtoxinA than patients with BEB for a similar duration of effect. Adverse events were dose related, and they occurred more frequently in patients who were given more units. CONCLUSIONS: Level I evidence supports the efficacy of Botox (Allergan Corp., Irvine, CA), Meditoxin, and Xeomin (Merz Pharmaceuticals, Frankfurt am Main, Germany) for the treatment of BEB. Meditoxin and Botox have equivalent effectiveness and incidence of adverse events for BEB and HFS. Dysport (Ipsen Biopharmaceuticals, Inc, Paris, France) seems to have efficacy similar to Botox and Meditoxin for BEB and HFS, but any definitive conclusions from the 2 level II studies in this review are limited by differences in the methodologies used. Higher doses of Botox and Dysport result in more adverse events. Repeated treatments using Botox seem to maintain efficacy for treatment of facial dystonias over a follow-up period of at least 10 years, based on level III evidence.

Orbital Implants in Enucleation Surgery: A Report by the American Academy of Ophthalmology.

PURPOSE: To compare the motility and complication rates of porous and nonporous implants after enucleation surgery. METHODS: Literature searches of the PubMed and Cochrane Library databases were last performed in February 2017 to identify studies published between 2003 and 2017 on outcomes after enucleation surgeries in which a variety implants were used. The searches were limited to the English language with abstracts and yielded 43 articles, which the Ophthalmic Technology Assessment Committee Oculoplastics and Orbit Panel reviewed for relevancy. Twenty-five articles were considered to have met the search strategy, and the panel methodologist assigned ratings to them according to the level of evidence. RESULTS: Only 2 of the 25 articles identified met the criteria for level I evidence. Eighteen of the studies did not assess motility after enucleation surgery, and the 7 that did evaluate this metric involved porous implants. The studies that analyzed this outcome reported favorable results, but the results were not uniformly based on objective analysis. Both porous and nonporous implants were well tolerated, and complication rates were generally low for both types. CONCLUSIONS: In keeping with increasing surgeon preference for porous implants, most studies identified in this literature search involved the use of this type of implant. These implants resulted in excellent motility after enucleation surgery, although many studies did not assess this outcome. Regardless of implant type, major complications were rare, and infection was exceptionally uncommon after enucleation. Given the paucity of data on motility and the absence of direct, objective comparisons of porous and nonporous implants, definitive conclusions about the impact of implant material on motility cannot be made. Since few studies evaluated nonporous implants, direct comparisons cannot be made definitively between implant types, and future investigations are needed to enable a critical assessment.

Treatments for Ocular Adnexal Lymphoma: A Report by the American Academy of Ophthalmology.

PURPOSE: To review the literature to determine the efficacy of available treatments for ocular adnexal lymphoma (OAL) and to evaluate the outcomes and complications of treatments in patients older than 13 years. METHODS: A literature search was conducted last in March 2017 in the PubMed and Cochrane Library databases for English-language original research investigations that evaluated treatment outcomes for OAL. The searches identified 307 unique citations, and 27 studies were selected according to the criteria outlined for this assessment. RESULTS: The 27 studies reviewed comprised 2009 patients. Seventy-five percent of the cases reported were extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT). Twenty-five studies reported results using radiotherapy with or without chemotherapy or surgery. The local control rate of MALT lymphomas with treatments involving radiotherapy averaged 95.9%. Distant and local relapses can occur, and in studies reporting only on MALT lymphomas (884 patients), the 5-year and 10-year disease-free survival rates were reported to be 86.4% and 78.7%, respectively. However, overall survival in patients receiving radiotherapy remained very good, with the 5-year and 10-year survival rates reported to be 93.8% and 84.9%, respectively. Studies that included data on multiple histologic subtypes of lymphoma or non-MALT lymphomas (988 patients) reported local control rates to be 93.1%; 5-year and 10-year disease-free survival rates to be 75.7% and 71.0%, respectively; and 5-year and 10-year overall survival rates to be 78.9% and 73.5%, respectively. Studies on the use of doxycycline for MALT lymphomas (137 patients) reported complete responses of between 4.4% and 13%. Complete and partial responses combined were between 26.7% and 65%. Disease-free survival was not reported for these 2 studies, although progression-free survival was reported to be between 55% and 60.9%. The most frequently reported complications of treatment were cataracts (12.1%) and dry eye (8.5%). CONCLUSIONS: For MALT lymphomas, local control, disease-free survival, and overall survival are good with radiation treatment. The results of treatment of non-MALT lymphomas using radiotherapy also were good, but they were not as favorable as the treatment results of MALT lymphomas.

Spheno-Orbital Meningiomas: An Analysis Based on World Health Organization Classification and Ki-67 Proliferative Index.

PURPOSE: To evaluate the clinical behavior of spheno-orbital meningiomas with regard to World Health Organization (WHO) tumor grade and Ki-67, a cellular marker of proliferation. METHODS: A retrospective review over a 16-year period of the demographic, clinical, radiographic, and surgical data of all patients with spheno-orbital meningioma who underwent surgical resection. Tumor specimens were examined histologically using the current WHO 2016 classification and immunohistochemically using Ki-67/MIB-1 monoclonal antibody. RESULTS: Thirty-eight patients met all inclusion criteria: 78.9% of tumors were WHO grade I with a mean Ki-67 of 3.76, and 93% of patients were clinically stable at last follow up; 10.5% of lesions were WHO grade II (atypical) with a mean Ki-67 of 14.93, and 10.5% of lesions were WHO grade III (anaplastic) with a mean Ki-67 of 58.3. All grade II and III meningiomas exhibited an aggressive clinical course. There were statistically significant correlations between disease clinical progression and WHO tumor grade (p < 0.001), between disease clinical progression and Ki-67 (p < 0.001), and between increasing Ki-67 index and higher WHO grade (p < 0.001). For WHO grade I lesions, a Ki-67 of ≥3.3 correlated with recurrence (p = 0.0256). Overall, disease-specific mortality occurred in 5 (13%) patients. CONCLUSIONS: Ki-67 index is a valuable marker to use in conjunction with WHO grade to predict meningioma behavior, particularly in histologically borderline lesions, and possibly to identify a subset of WHO grade I tumors at risk of recurrence. This combination of methods can aid in tailoring treatment and surveillance strategies.

Naso- or Orbitocutaneous Fistulas after Free Flap Reconstruction of Orbital Exenteration Defects: Retrospective Study, Systematic Review, and Meta-Analysis.

Objective Naso- or orbitocutaneous fistula (NOF) is a challenging complication of orbital exenteration, and it often requires surgical repair. We sought to identify the incidence and risk factors for NOF after orbital exenteration. Study Design Retrospective chart review, systematic review, meta-analysis. Setting Tertiary care center. Participants Patients undergoing free flap reconstruction following orbital exenteration. Records were reviewed for clinicopathologic data, operative details, and outcomes. Main Outcome Measures Univariate analysis was used to assess risk factors for incidence of postoperative NOF. PubMed and Cochrane databases were searched for published reports on NOF after orbital exenteration. Rates of fistula and odds ratios for predictive factors were compared in a meta-analysis. Results Total 7 of 77 patients (9.1%) developed NOF; fistula formation was associated with ethmoid sinus involvement ( p < 0.05) and minor wound break down ( p < 0.05). On meta-analysis, pooled rates of fistula formation were 5.8% for free flap patients and 12.5% for patients receiving no reconstruction. Conclusion Immediate postoperative wound complications and medial orbital wall resection increased the risk for NOF. On review and meta-analysis, reconstruction of orbital exenteration defects decreased the risk for fistula formation, but published series did not demonstrate a significant decrease in risk with free flaps compared with other methods of reconstruction.

Consensus on Diagnostic Criteria of Idiopathic Orbital Inflammation Using a Modified Delphi Approach.

Importance: Current practice to diagnose idiopathic orbital inflammation (IOI) is inconsistent, leading to frequent misdiagnosis of other orbital entities, including cancer. By specifying criteria, diagnosis of orbital inflammation will be improved. Objective: To define a set of criteria specific for the diagnosis of IOI. Design, Setting, and Participants: A 3-round modified Delphi process with an expert panel was conducted from June 8, 2015, to January 25, 2016. Fifty-three orbital scientist experts, identified through membership in the Orbital Society, were invited to participate in on online survey and they scored, using 5-point Likert scales, items that are eligible as diagnostic criteria from the literature and from personal experience. The items were clustered around the anatomic subtypes of IOI: idiopathic dacryoadenitis and idiopathic orbital fat inflammation (2 nonmyositic IOIs), and idiopathic orbital myositis (myositic IOI). Items with dissensus were rescored in the second round, and all items with consensus (median, ≥4; interquartile range, ≤1) were ranked by importance in the third round. Main Outcomes and Measures: Consensus on items to be included in the criteria. Results: Of the 53 experts invited to participate, a multinational panel of 35 (66%) individuals with a mean (SD) years of experience of 31 (11) years were included. Consensus was achieved on 7 of 14 clinical and radiologic items and 5 of 7 pathologic items related to diagnosis of nonmyositic IOI, and 11 of 14 clinical and radiologic items and 1 of 5 pathologic items for myositic IOI. There was agreement among panelists to focus on surgical tissue biopsy results in the diagnosis of nonmyositic IOI and on a trial with systemic corticosteroids in myositic IOI. Panelists agreed that a maximum number of 30 IgG4-positive plasma cells per high-power field in the orbital tissue is compatible with the diagnosis of IOI. Conclusions and Relevance: An international panel of experts endorsed consensus diagnostic criteria of IOI. These criteria define a level of exclusion suggested for diagnosis and include tissue biopsy for lesions not confined to the extraocular muscles. This consensus is a step toward developing guidelines for the management of IOI, which needs to be followed by validation studies of the criteria.