Bilateral orbital pseudotumor as the initial manifestation of granulomatosis con poliangeítis (GPA) in a child: A case report

Abstract

Orbital pseudotumor is uncommon in children and may rarely herald anti‑neutrophil cytoplasmic antibody (ANCA)–associated vasculitis. We report a 4‑year‑old girl who presented with progressive bilateral proptosis due to extraconal–intraconal inflammatory masses. Histopathology showed small‑ and medium‑vessel changes with features suggestive of vasculitis, and serology was MPO‑p‑ANCA–positive. Taken together with the clinical–radiologic pattern and exclusion of neoplasm, infection, and histiocytosis, the findings supported a diagnosis of granulomatosis con poliangeítis (GPA) with orbital‑predominant disease. The child improved with high‑dose corticosteroids and cyclophosphamide. This case underscores that an orbital pseudotumor—although rare—can be the sentinel manifestation of systemic vasculitis in pediatrics; early biopsy, targeted ANCA testing, and multidisciplinary management are critical to preserve vision and guide therapy.

Introduction

Granulomatosis con poliangeítis (GPA) is an ANCA‑associated small‑ to medium‑vessel vasculitis that may involve virtually any organ system. Ocular disease is well recognized in GPA; however, orbital pseudotumor (idiopathic orbital inflammation, IOI) as the initial and dominant presentation in young children is unusual [[1], [2]]. Because imaging overlaps with neoplasms and other inflammatory conditions, biopsy and ancillary tests are often required. We present a pediatric case in which bilateral orbital pseudotumor was the first manifestation of GPA and outline diagnostic pearls for radiologists and clinicians.

Case presentation

A 4‑year‑old previously healthy girl presented with 4 months of progressive left periorbital swelling and ocular misalignment, later evolving to bilateral proptosis. Past medical history was unremarkable and immunizations were up to date. There was no history of recurrent sinusitis, asthma, allergic disease, oral ulcers, chronic cough, hematuria, epistaxis, or skin rash. Family history was negative for autoimmune or rheumatologic disorders. On examination, visual acuity was hand‑motion in the left eye and 20/40 in the right eye, with left hypotropia and limited supraduction, firm infraorbital induration, and axial proptosis (left greater than right). There was no fever or constitutional illness and no palpable lymphadenopathy.

Magnetic resonance imaging (MRI) of the orbits demonstrated bilateral solid extraconal masses with intraconal extension, involving the lacrimal glands and multiple extraocular muscles, more extensive on the left, compatible with an orbital inflammatory pseudotumor pattern (Fig. 1). Axial T1‑weighted MRI also revealed proptosis with increased anterior globe projection beyond the interzygomatic line (Fig. 2). Computed tomography (CT) of the orbits showed a soft‑tissue density mass predominantly on the left side, resulting in proptosis but without bone erosion or remodeling (Fig. 3).

Fig. 1.

Orbital MRI findings. (A) Axial T1-weighted image shows hypointense extraconal lesions (yellow arrow). (B) Coronal T2-weighted image demonstrates hypointense extraconal masses involving the superior rectus muscle and lacrimal gland, more prominent on the left side (yellow arrow). (C) Axial diffusion-weighted image (b = 1000) reveals diffusion restriction within the bilateral orbital lesions. (D) Coronal postcontrast fat-suppressed T1-weighted image shows avid enhancement of the lesions (yellow arrow), without optic nerve involvement (red arrow).

Fig. 2.

Axial T1-weighted orbital MRI. Demonstrates left-predominant proptosis with increased anterior globe projection beyond the interzygomatic line (green line), consistent with orbital mass effect.

Fig. 3.

Noncontrast orbital CT. (A) Axial soft-tissue window and (B) bone window images reveal a left-predominant extraconal soft-tissue mass causing proptosis. No evidence of osseous destruction or remodeling is observed.

Initial ancillary tests included a normal transthoracic echocardiogram and normal contrast‑enhanced chest and abdominopelvic CT. Serologic studies showed MPO‑p‑ANCA positivity; antinuclear antibodies and extractable nuclear antigens were negative; anti‑dsDNA was negative; serum IgG4 was within reference range. A complete blood count showed mild leukocytosis within age‑adjusted reference intervals; C‑reactive protein and erythrocyte sedimentation rate were mildly elevated (reference: ESR 0–20 mm/h, CRP 0–5 mg/L). Urinalysis showed no proteinuria or hematuria; estimated glomerular filtration rate was appropriate for age (>90 mL/min/1.73 m²). Liver chemistries and electrolytes were within pediatric reference ranges.

Excisional biopsy from the left orbital mass initially suggested histiocytosis at an outside institution; re‑evaluation at our center excluded histiocytosis and neoplasia. Hematoxylin–eosin sections demonstrated fibroadipose tissue with a polymorphous inflammatory infiltrate rich in lymphocytes, plasma cells, and eosinophils, with patchy small‑ and medium‑caliber vessel wall changes, including endothelial swelling, fibrinoid‑like degeneration, and perivascular neutrophils with leukocytoclasia. Scattered poorly formed microgranulomas were noted adjacent to vessel walls. No organisms were identified on special stains. These findings were interpreted as changes suggestive of vasculitis in the appropriate clinical context.

Multidisciplinary consensus favored GPA with orbital‑predominant disease. Induction therapy with intravenous methylprednisolone pulses was followed by oral prednisolone taper and intravenous cyclophosphamide. The child improved clinically with reduction of proptosis and recovery of visual acuity to 20/25 (right eye) and 20/40 (left eye) at early follow‑up, without treatment‑related complications.

Discussion

GPA is a rare pediatric vasculitis; orbital involvement is recognized but mass‑like pseudotumor as the sentinel presentation in early childhood is uncommon [3]. Radiologists should recognize that bilateral extraconal–intraconal inflammatory masses with lacrimal gland and extraocular muscle involvement can reflect GPA rather than idiopathic disease [[4], [5]]. This case adds to the literature by illustrating MPO‑p‑ANCA–positive, orbit‑limited GPA with biopsy findings suggestive of vasculitis in a child.

GPA typically affects the upper airways, lungs, and kidneys; isolated orbital predominance is less frequent in children. However, pediatric series highlight that orbital mass lesions may occur in ANCA‑associated vasculitides and can mimic IOI [[6], [7]]. Recent pediatric reports indicate that orbit‑limited or limited GPA may more often be MPO‑p‑ANCA–positive than classic systemic GPA, explaining this presentation.

Histopathology demonstrated endothelial swelling, fibrinoid‑like change, and perivascular neutrophilic infiltration with leukocytoclasia, supporting a vasculitic process. Negative stains for organisms and exclusion of histiocytosis strengthened this interpretation.

This case is unique due to the patient’s young age, bilateral orbital involvement, and MPO‑p‑ANCA positivity without systemic disease, underscoring the diagnostic importance of imaging and biopsy correlation.

Conclusions

Orbital pseudotumor, although infrequent, can be the first clinical clue to systemic vasculitis in children and should prompt consideration of ANCA‑associated disease. Early imaging, targeted serology, and timely biopsy are essential to expedite diagnosis and protect vision.

Patient consent

We declare we have obtained he respective informed consent regarding clinical history and images endorsed by hospital ethics committee.