ANCA-negative Destructive Sinonasal Granulomatosis with Polyangiitis Mimicking Invasive Fungal Rhinosinusitis in a Child

Abstract

Introduction: Granulomatosis with polyangiitis (GPA) is a rare pediatric small-vessel vasculitis that

may present with localized upper airway involvement. Destructive sinonasal disease can mimic

invasive fungal infection or malignancy, particularly in ANCA-negative patients, leading to diagnostic

delay. Objectives: To describe the clinical, radiologic, and histopathologic features of a pediatric

patient with ANCA-negative destructive sinonasal GPA initially suspected as invasive fungal

rhinosinusitis. Methods: We report the case of a 7-year-old girl presenting with progressive unilateral

facial edema, dacryocystitis, and destructive sinonasal disease. Clinical records, imaging studies,

histopathology, and laboratory findings were reviewed. Results: The patient developed progressive

right periorbital and hemifacial edema associated with dacryocystitis and a painful palatal ulcer. Initial

computed tomography demonstrated heterogeneous occupation of the right maxillary sinus with bone

lysis and extension to the ipsilateral nasolacrimal duct, raising suspicion for invasive fungal

rhinosinusitis or neoplastic disease. Despite broad-spectrum antimicrobial and antifungal therapy,

disease progression persisted. Magnetic resonance imaging later demonstrated diffuse inflammatory

occupation of the right maxillary, ethmoidal, and sphenoidal sinuses with focal bone erosion, mucosal

necrosis, and extension into adjacent soft tissues. High-resolution chest computed tomographyadditionally demonstrated focal areas of air trapping suggestive of small airway involvement despite

the absence of significant respiratory symptoms. Histopathologic examination of maxillary sinus and

palatal biopsies revealed necrotizing granulomatous small-vessel vasculitis with fibrinoid necrosis,

prominent leukocytoclasia, eosinophil-rich inflammation, and granuloma formation, without evidence

of pathogenic microorganisms on special stains. ANCA testing was negative. Based on the clinical,

radiologic, and histopathologic findings, a diagnosis of ANCA-negative granulomatosis with

polyangiitis was established. Conclusion: Pediatric GPA may present as destructive unilateral

sinonasal disease closely mimicking invasive fungal rhinosinusitis. In children with progressive

sinonasal destruction, palatal ulceration, and negative microbiologic studies, GPA should be

considered even in the absence of ANCA positivity. Early biopsy and multidisciplinary evaluation are

critical to establish the diagnosis and avoid delays in immunosuppressive treatment.