Seronegative granulomatosis with polyangiitis presenting as an acute skull base osteomyelitis with multiple cranial neuropathies

Abstract

Granulomatosis with polyangiitis (GPA, formerly Wegener’s) is a rare form of vasculitis, commonly affecting the upper and lower respiratory tract with simultaneous glomerulonephritis. Ear, nose and throat (ENT) manifestations account for the majority of presentations. The presence of antineutrophil cytoplasmic antibody is a recognized hallmark of GPA, but clinicians should remain cautious of false negative results. We describe a rare case of GPA presenting with concurrent middle ear disease and multiple lower cranial nerve palsies. Clinical judgment was affected by repeated negative autoimmune screens, and a definitive diagnosis was only achieved following renal biopsy. Reported cases of GPA presenting with mastoiditis or cranial nerve involvement are typically seropositive, with seronegative GPA following a less aggressive process. This case highlights the importance of clinical suspicion in the face of treatment resistant ENT pathology, and the need for early histopathological analysis. Early diagnosis and treatment are crucial in limiting disease progression.

Radiologic Differentiation between Granulomatosis with Polyangiitis and Its Mimics Involving the Skull Base in Humans Using High-Resolution Magnetic Resonance Imaging

“…It is often challenging to diagnose GPA in clinical practice when patients present with nonspecific symptoms [9][10][11][12][13][14][15][16][17][18]. In particular, when GPA affects the head and neck, the absence of symptom specificity and the clinical variability of the head and neck manifestations often contribute to the misdiagnosis of the disease as an infectious or neoplastic condition [3,[9][10][11][12][13][14][15][16][17][18]25].…”

“…It is often challenging to diagnose GPA in clinical practice when patients present with nonspecific symptoms [9][10][11][12][13][14][15][16][17][18]. In particular, when GPA affects the head and neck, the absence of symptom specificity and the clinical variability of the head and neck manifestations often contribute to the misdiagnosis of the disease as an infectious or neoplastic condition [3,[9][10][11][12][13][14][15][16][17][18]25]. Patients with GPA involving the skull base and/or the Eustachian tube may manifest otologic symptoms mainly, but possibly accompanied by constitutional symptoms and a high serologic inflammatory marker, such as the erythrocyte sedimentation rate (ESR) [15,17], which may clinically mimic SBO.…”

“…Unfortunately, radiological findings may lead to an erroneous diagnosis as well because the radiologic features of GPA often overlap with those of other diseases [9][10][11][12][13][14][15][16][17][18]29], delaying the time to diagnosis [3,23,[29][30][31]. Accordingly, it is not surprising that there have been several case reports published on GPA cases in which the MRI findings mimicked those of SBO or NPC [9][10][11][12][13][14][15][16][17][18]29], or that, to date, no studies have identified MRI findings possessing diagnostic value for differentiating between these diseases. Nevertheless, the advent of high-resolution MRI has facilitated a more detailed assessment of the imaging characteristics and the extent of such lesions, and the diagnostic role of MRI is expanding.…”

“…Otologic impairment in patients with GPA can develop when the disease involves the skull base or the Eustachian tubes, and it is often accompanied by nasopharyngeal manifestations [8]. Therefore, in such cases, it can be challenging to discriminate GPA from the infectious processes driving skull base osteomyelitis (SBO) and the malignant processes involving the nasopharynx [9][10][11][12][13][14][15][16][17][18]. Although serum ANCA screening can provide evidence for the diagnosis of GPA, this test is not routinely performed, but selectively ordered for the patients with clinical suspicion in the daily practice.…”

“…Several case reports have described magnetic resonance imaging (MRI) findings in patients with these three disease categories; however, their imaging characteristics mimic each other and the results have been shown to be inconclusive [9][10][11][12][13][14][15][16][17][18]. To our knowledge, few studies have investigated the discriminative value of MRI in differentiating GPA from infective osteomyelitis and nasopharyngeal carcinoma (NPC) involving the skull base.…”