A Rare Case of “BOOP-Like” Variant of Granulomatosis With Polyangiitis (Wegner's)

Abstract

INTRODUCTION: Wegener's granulomatosis (WG) is a systemic vasculitis that usually involves the lungs, upper respiratory tract and kidneys. Histological manifestations in the lung are typically characterized by necrotizing granulomatous inflammation alongwith extensive parenchymal necrosis and necrotizing vasculitis. Several histological variants have been recognized and are characterized by bronchocentric inflammation, marked eosinophil infiltrate, alveolar hemorrhage or interstitial fibrosis. A more uncommon variant of Wegener's is a "BOOP-like" variant primarily consisting of bronchiolitis obliterans-organizing pneumonia like fibrosis; only 16 such cases have been described in the literature to date. CASE PRESENTATION: A 63 year-old woman with limited medical history presented with acute left flank pain and acute renal failure. Her physical exam was notable only for mild left costophrenic angle tenderness. Her urine-analysis revealed nephritic range proteinuria, minimal pyuria, and no red or white blood cell casts. A CT-Abdomen showed mild periureteric and left renal hilum fat stranding. Extra-renal abnormalities consisted of bilateral, multiple pulmonary nodules (largest 1.3 X 1.0 cm) and an enlarged right paratracheal lymph node. When specifically asked, she admitted to a chronically dry nose and epistaxis. Her family history was notable for WG (uncle) and Polymyositis (father). A PET scan showed modest uptake in the pulmonary nodules; a V/Q scan was low-probability. Additional labs were notable for a positive ANA with speckled pattern. A p-ANCA was elevated only initially and SPEP, UPEP, Complement C3 and C4 levels were all normal. Her kidney biopsy revealed pauci immune crescentic glomerulonephritis. She underwent open lung biopsy which demonstrated areas of BOOP and necrotic parenchymal lesions with overlapping granulomatous inflammation and vasculitis suggestive of "BOOPlike variant of Wegener's granulomatosis". She was started on prednisone and cyclophosphamide. She showed good response with resolution of her renal failure and is doing well since then. DISCUSSION: WG is one of the most common forms of systemic vasculitis. Common presentations include recurrent sinusitis and epistaxis with 80% of the patients showing evidence of pulmonary involvement with cough, hemoptysis and dyspnea. The most common radiographic findings are pulmonary infiltrates and bilateral cavitary nodules. WG is usually associated with an elevated c-ANCA, but elevated p-ANCA (10%) or ANCA-negative (10%) cases do occur. CONCLUSIONS: Our patient is unique due to her presentation with predominant renal involvement and asymptomatic pulmonary involvement with variable p-ANCA positivity, multiple non-cavitary pulmonary nodules, and an unusual histopathological variant of WG consisting of BOOP-like changes.