Behçet’s disease (BD) is a systemic vasculitis that predominantly affects males. Eye involvement is common, occurs in 28-50% of cases, and is dominated by uveitis. ^{1 , 2}

A 28-year-old Tunisian male patient was admitted for right orbital protrusion and edema ( Figure 1) with local pain and intense helmet headache lasting for 15 days before admission.

Ophthalmological examination of the right eye revealed a visual acuity of 2/10. A painful non-pulsatile non-reducible exophthalmia with corneal edema, Tyndall to 2 crosses in the anterior chamber with iridocorneal synechia. Examination of the left eye revealed no abnormalities.

Both brain and orbital MRIs were performed using T1, T2, T2*, and Flair diffusion protocols with sagittal axial and coronal cuts with and without gadolinium injection.

Brain MRI revealed no cerebral venous thrombosis. Orbital MRI revealed thickening of the right anterior orbital soft tissues along with an important inflammatory signal in the extra conal fat, which was moderately enhanced by gadolinium injection, with no intra- or extra-conal soft tissue collection.

MRI also showed a discrete inflammatory signal abnormality with contrast enhancement of the right internal and upper right oblique muscles and periorbital inflammatory thickening associated with inflammatory myositis with no extension to the intra-conal or intracranial fat ( Figures 2– 5). No abnormalities were observed in the rest of the structures, especially in the optic nerves.

Physical examination revealed a history of recurrent oral aphthous and pseudofolliculitis. The remaining examinations revealed no abnormalities.

B5 HLA typing was negative, and pathergy test results were positive. The diagnosis of Behçet’s disease with inflammatory orbital pseudotumor was confirmed. A workup of the tumor was performed as follows: an ENT examination and bacterial and viral serologies. Thyroid balance, antinuclear antibodies, and tumor markers CEA – PSA, alpha FP, CA 19-9, chest radiographs, sinus, and pelvic abdominal ultrasound showed no abnormalities. Biopsy of the mass was not performed. The patient received three bolus doses of 1 g of methylprednisolone per day, each relayed with corticosteroid (1 mg/kg/day associated with colchicine at a dose of 1 mg/day).

The outcome was favorable after 5 days, with regression of the local inflammatory phenomena ( Figure 6). Examination of the control eye showed improvement in the right visual acuity to 9/10, persistent conjunctival injection with normal eye movements, and a quiet anterior segment with a normal eye bottom. The retinal angiography results were normal. Based on both clinical and examination data improvements, we did not opt for subsequent MRI control. The patient did not relapse after 6 months of follow-up.

The idiopathic orbital inflammatory syndrome was first described by Birch and Hirschfield in 1905. It is also known as orbital pseudotumor and represents a nonspecific and nonneoplastic inflammatory process of the orbit. ^{3 , 4} This condition most commonly involves extraocular muscles. Less commonly, there are inflammatory changes involving the uvea, sclera, lacrimal gland, and retrobulbar soft tissue. The exact etiology is unknown. The main differential diagnosis is malignant tumor progression. ^{5 , 6}

It represents 4.7 to 6.3% (depending on the series) of all orbital conditions. ⁷ We distinguished between localized and diffuse inflammatory pseudotumors of the orbit.

Myositis is the most frequent orbital-localized inflammatory pseudotumor. Orbital myositis is a form of idiopathic orbital inflammation, characterized by inflammation of the external eye muscles. It may lead to proptosis, periocular pain, and diplopia. ^{4 – 6}

The etiologies are dominated by infectious causes (Lyme disease and trichinosis), sarcoidosis, Crohn’s disease, systemic lupus, polyarteritis nodosa, rheumatoid arthritis, Wegner’s granulomatosis, and neoplastic causes. ^{4 , 5 , 8}

Diagnosis is based on radiological, histological, and clinical data.

The association between Behçet’s disease and inflammatory pseudotumor has rarely been reported, and the first observation was published in 1996, reporting an inflammatory pseudotumor of the terminal ileum in Behçet’s disease. ⁶ Other locations have been described: the heart, ⁹ brain, ¹⁰ and orbit. ^{11 – 13}

Myositis associated with Behçet’s disease is rare. It mainly affects the skeletal muscles. ⁷

There are few associations between orbital myositis and Behçet’s disease, as mentioned in Table 1. ^{7 , 8 , 11 , 12 – 14} It is rarely reported as an initial manifestation of Behçet’s disease, as illustrated in our case. ^{7 , 13 , 14} To the best of our knowledge, this is the fourth reported case of Behçet’s disease caused by an inflammatory orbital pseudotumor.

As orbital biopsies are rarely done, radiological diagnosis is sufficient. ⁷

Treatment is based on corticosteroids, ^{7 – 9} as is the case in our patient. However, it may be refractory to corticosteroid therapy. Sometimes, immunosuppressive drugs are also required. ^{7 , 15} The prognosis is favorable with this type of treatment, apart from some recalcitrant forms that require the use of TNF blockers. ¹⁶

Rituximab has demonstrated effectiveness in cases resistant to glucocorticoids, surgery, or radiation therapy. This finding indicates that rituximab may be a valuable treatment option for managing this condition. ^{17 , 18}

The association between Behçet’s disease and the inflammatory pseudotumor of the orbit is exceptional. Orbital inflammation should be considered as an ophthalmic manifestation of Behçet’s disease and treated precociously to preserve the visual prognosis.

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Dr. Sameh Sayhi: Revising the article, approval of the work, and agreeing to be held accountable.