SESSION TITLE: Fellows Pulmonary Manifestations of Systemic Disease Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: October 18-21, 2020 INTRODUCTION: Granulomatosis with polyangiitis (GPA) is a small to medium vessel vasculitis, usually ANCA positive. Clinically this disease is difficult to diagnose, as presentations vary. Patients can have ear, nose, and sinus disease as well as rapidly progressive glomerulonephritis.1 Renal complications occur in up to 75% of patients.1 Rare pulmonary complications include alveolar hemorrhage, nodules, and cavitary lesions. Seldom these patients have mediastinal lymphadenopathy and obstructive lung disease.2 Here we present a case of a woman who developed pulmonary nodules, lymphadenopathy, and obstructive lung disease due to GPA. CASE PRESENTATION: Our patient is a 75yo female nonsmoker with a history of polymyalgia rheumatica in remission that endorsed one year of dyspnea on exertion, hoarseness, and 20 lb weight loss. PFTs noted obstructive ventilatory defect meeting criteria for severe COPD. CT chest revealed multiple pulmonary nodules, mediastinal lymphadenopathy, and emphysematous change throughout of unknown duration as she did not have any previous imaging. CT-guided biopsy pathology showed chronic inflammatory changes, but no malignant cells. PET scan had hypermetabolic nodules bilaterally worrisome for metastasis. Bronchoscopy noted subglottic edema, but we were unable to pass ETT, so EBUS and ENB were aborted. She was noted to have mucosal inflammation throughout the tracheobronchial tree. Repeat CT-chest showed bilateral spiculated nodules increasing in size and number compared to prior scan. Second CT-guided biopsy pathology showed chronic inflammation and fibrosis with small noncaseating granulomas. Based on in-house and outside pathology consult, it was decided she likely had GPA. After evaluation by rheumatology she started rituximab infusions, but pulmonary nodules remained stable in size. P and c-ANCA were negative, along with negative c-ANCA by immunofluorescence. RF, CCP, ESR, CRP and renal function were within normal limits. CT maxillofacial was negative. DISCUSSION: When a vasculitis is suspected, a negative ANCA does not exclude the diagnosis of GPA, so further investigations, such as biopsy, should be considered. The lung is the most common site biopsied. Our case presented a diagnostic challenge given her presentation with a COPD-like syndrome and significant weight loss, as well as p-ANCA negativity. By some estimates <10% of cases of GPA present with isolated disease, such as in our patient.3 CONCLUSIONS: Prompt diagnosis for GPA is needed as the mortality is high without treatment. Treatment includes immunosuppression with glucocorticoids, methotrexate, azathioprine or cyclophosphamide.1 Our case highlights the importance of the pathologist in the diagnosis of small vessel vasculitis to lead the care team to the correct and rapid diagnosis. Reference #1: Seo P, Stone JH. The Antineutrophil Cytoplasmic Antibody-Associated Vasculitides. Am J Med. 2004; 117: 39-50. Reference #2: George TM, Cash JM, Farver C, et al. Mediastinal mass and hilar adenopathy: rare thoracic manifestations of Wegener's granulomatosis. Arthritis Rheum. 1997;40:1992–1997. Reference #3: Ananthakrishan L, Sharma N, Kanne JP. Wegner's Granulomatosis in the Chest: High-Resolution CT Findings. AJR 2009: 192; 676-682. DISCLOSURES: My spouse/partner as a Consultant relationship with Abbvie Please note: $1-$1000 Added 05/27/2020 by Ebtesam Islam, source=Web Response, value=Consulting fee No relevant relationships by Ximena Solis, source=Web Response