Granulomatosis with polyangiitis (GPA) is a systemic vasculitis that usually involves the lungs, upper respiratory tract and kidneys. Common presentations include recurrent sinusitis and epistaxis as seen in 90% of the cases to nonspecific arthralgias & arthritis. Approximately 80% of patients with GPA have pulmonary involvement during the course of their disease. Pulmonary symptoms include cough, hemoptysis, dyspnea, and sometimes pleuritic chest pain The most common radiographic findings are pulmonary infiltrates and nodules. Nodules are usually multiple and bilateral and often cavitary. Immunologic work up of GPA usually shows elevated c-ANCA but can also manifest as elevated p-ANCA in 10% of the cases. Also, it has been shown that 10% of the cases are ANCA negative. Current remission induction treatment of severe ANCA-associated vasculitis consists of high dose corticosteroids and pulsed intravenous cyclophosphamide. Although there have been major improvements in treatment protocols leading to decreased treatment related toxicity, still the current treatment regimens are associated with considerable morbidity. INTRODUCTION REFERENCES CASE A Rare Case of “BOOP-Like” Variant of Granulomatosis With Polyangiitis DISCUSSION We present an unusual case of GPA with predominant renal involvement and asymptomatic pulmonary involvement in form of non-cavitary multiple bilateral nodules with inconsistent ANCA positivity and histological findings suggestive of a rarely found and described “BOOP like variant of granulomatosis with polyangiitis.” GPA is one of the most common forms of systemic vasculitis and typically involves medium and small sized blood vessels. Histological manifestations in the lungs are typically characterized by the combination of necrotizing granulomatous inflammation with extensive parenchymal necrosis and a necrotizing vasculitis. Several histological variants have been recognized, including cases characterized by bronchocentric inflammation, a marked eosinophil infiltrate, alveolar hemorrhage, and capillaritis or interstitial fibrosis. Another uncommon variant of GPA is a “BOOP-like” variant, characterized by bronchiolitis obliterans-organizing pneumonia (BOOP)-type fibrosis as the major histological finding. The clinical presentation and course of GPA can be highly variable, and this variability may be due to differences in host responses. It is conceivable, then, that the extensive BOOP-like areas observed in our patients may represent an unusual host response. There are no differentiating clinical features to distinguish BOOP-like and ordinary GPA. A limited form of Wegener's granulomatosis with BOOP-like variant in an ulcerative colitis patient. Intern Med Nov;41(11): BOOP-like variant of Wegener’s granulomatosis. A clinicopathologic study of 16 cases. Am J Surg Pathol Jul;20(7): Surgical pathology of the lung in Wegener’s granulomatosis. Review of 87 open lung biopsies from 67 patients. Am J Surg Pathol Apr;15(4): CONCLUSION We report a rare pathologic variant of granulomatosis with polyangiitis or WG with an atypical clinical presentation without any respiratory symptoms and primary renal involvement. Presentation A 63 year old Caucasian Woman with a past medical history of hypertension, anemia, hyperlipidemia, hypothyroidism, gastric antral vascular ectasia (GAVE) and mild intermittent asthma presented to ER with left flank pain. Physical Exam Her physical exam was notable for good air entry in her lungs bilaterally with no evident added sounds and mild left costophrenic angle tenderness. Her cardiac and abdominal exam did not reveal any abnormal findings. Lab Data and Imaging Lab workup revealed a normal white count, nephritic range proteinuria, minimal pyuria, and no red or white blood cell casts. CT scan (Figure 1, 2 and 3) of her abdomen revealed left renal hilum fat stranding changes and incidental finding of multiple bilateral pulmonary nodules largest 1.3 X 1.0 cm in dimension and a mildly enlarged Right paratracheal lymph node. Hospital Course Further work up was started to rule out other causes of acute kidney injury including contrast induced nephropathy, underlying malignancy and various pulmonary renal syndromes such as Churg Strauss, GPA/ MPA. Additional labs were notable for a positive ANA (titer 1:640) with speckled pattern. A p- ANCA was elevated only at the OSH (1:160). SPEP, UPEP, complement C3 and C4 levels were all normal. A PET scan (Figure 4) showed modest uptake in the pulmonary nodules. Further work up revealed a negative V/Q scan and her EGD confirmed the diagnosis of gastric antral vascular ectasia but did not show any other lesions/ pathology. Her AFB and fungal testing revealed negative results consistently. Diagnosis Her kidney biopsy showed pauci immune crescentic glomerulonephritis. Subsequently, she underwent open lung biopsy which demonstrated areas of bronchiolitis obliterans-organizing pneumonia, necrobiotic parenchymal lesions, granulomatous inflammation and vasculitis suggestive of “BOOP-like variant of Wegener’s granulomatosis” or as now known as granulomatosis with polyangiitis. Treatment She was started on prednisone and cyclophosphamide and showed good response with resolution of her renal failure. She is being regularly followed up by her PCP and is doing well till date. Photomicrographs showing 1. Irregularly shaped suppurative granulomas within inflamed fibrous background in the areas of BOOP. 2. Typical vasculitis of Wegener’s granulomatosis or GPA with necrotizing granulomatous inflammation of medium sized artery wall. Reproduced from The American Journal of Surgical Pathology Issue: Volume 20(7), July 1996, pp Copyright: © Lippincott-Raven Publishers. Figure 1, 2 and 3: Coronal sections of the CT-Thorax showing multiple nodular lesions in the lung parenchyma. Figure 4: Coronal section of the PET Scan showing increased uptake in one of the nodular lesions as seen on CT-Thorax Deepankar Sharma 1 MD, Neil R. Aggarwal 2 MD 1. Wake Forest University School of Medicine, Department of Pulmonary and Critical Care Medicine, Winston Salem, NC 2. Johns Hopkins University School of Medicine, Department of Pulmonary and Critical Care Medicine, Baltimore, MD