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Granulomatosis with polyangiitis (GPA) presenting as thick-walled cavitary lung lesion.

A 58-year-old female with a history of psoriatic arthritis on immunosuppressive therapy presented to the clinic with flu-like symptoms, cough, and blood-tinged sputum for one week. She denied chills, night sweats, wheezing, chest pain, weight loss, joint pain, or muscle aches. She had smoked for 31 pack-years and quit 1 year earlier. She was born and lived in upstate New York with no previous exposure to tuberculosis (TB). She had no exposure to chemicals or bird or bat droppings. There was no recent history of travel to any fungal endemic areas. Her home medications included albuterol, fluticasone-salmeterol, montelukast, omeprazole and citalopram. Her physical examination was completely normal, and she had a white blood cell count of 13.8 10/l with a platelet count of 63 10/ml. She was prescribed amoxicillin/clavulanate for presumed pneumonia. Because of the persistence of symptoms, imaging studies were done. Chest x-ray showed a cavitary lesion with an air-fluid level in the right upper lobe (Figure 1A ). Computed tomography of the chest demonstrated a cavitary mass with irregular thick walls and air-fluid level, as well as a 1.1 0.8 cm rounded subpleural nodule in the anterior left upper lobe (Figure 1B). Bronchoscopic washings were negative for malignancy and infectious workup for bacteria including TB and fungi were negative. Biopsy of the left lung nodule showed extensive necrotizing suppurative granulomatous inflammation consistent with granulomatosis with polyangiitis. Her proteinase 3 ANCA levels were also elevated which supported the diagnosis. The patient was started on rituximab and prednisone with improvement in her symptoms. Differential diagnosis of a cavitary lesion in the lung is broad. Infectious causes include bacterial pathogen, fungal or TB infection. Noninfectious causes include malignancy and systemic inflammatory diseases, such as rheumatoid arthritis or granulomatosis with polyangiitis. Granulomatosis with polyangiitis is a multisystem disease that involves multiple organs especially the lungs and kidneys. The frequent lung manifestations are nodules and infiltrates. Cavitation of the nodules occurs in 25% of nodules when they are > 2 cm, and the presentation of a solitary cavitary lesion is a rare phenomenon.