A Case with Pulmonary Alveolar Proteinosis and Sarcoidosis
Introduction: Autoimmune pulmonary alveolar proteinosis (PAP) is a rare lung disease caused by autoantibodies against GM-CSF. Sarcoidosis is a systemic granulomatosis mostly involving the lung. The pathogenesis of both immune mediated disorders remains unclear.
Case Report: 55 years old female patient presented with dyspnoea and cough in the hospital in Stuttgart. High-resolution computed tomography (HRCT) demonstrated ground glass opacities with crazy paving pattern, which was compatible with pulmonary alveolar proteinosis (PAP). Bronchoalveolar lavage (BAL) and tranbronchial lung biopsy (TBB) were typical for PAP. Mediastinal or hilar lymph nodes were not enlarged. Patient had occupational exposure to dusts at work in a printing office, and previous smoking history. Whole lung lavage (WLL) in both lungs was performed because of increased alveolar-arterial gradient (AaO2) at exercise test. 3 months after WLL HRCT showed partial regression of ground glass opacity.
7 months after diagnosis patient was referred to Ruhrlandklinik for a second opinion of treatment options. Forced vital capacity was 116% pred. and diffusion capacity (DLCO) 84% was predicted. At rest saturation was 98% and there was no change in saturation or AaO2 at exercise. In serum LDH was elevated to 309 IU/l (norm < 248 IU/l) and GM-CSF autoantibody was increased to 57 mcg/mI (norm < 10 mcg/ml). PAP was defined as stable and no further treatment was recommended.
15 months after diagnosis patient was admitted again in the Stuttgart hospital with marked fatique but no respiratory symptoms. Chest x-ray and computed tomography showed marked enlargement of mediastinal and hilar lymph nodes. The lung parenchyma was normal, consistent with PAP in complete remission. EBUS confirmed enlarged lymph nodes and cytology of transbronchial needle aspiration revealed non-caseating granuloma with features consistent with sarcoidosis. No changes in pulmonary function tests or DLCO were seen in follow-up. Diagnosis of sarcoidosis stage I was made. A wait and see strategy was chosen.
Discussion: This is a rare coincidence of sarcoidosis developing in a patient with autoimmune PAP in remission. Higher incidence of autoimmune diseases has been described in sarcoidosis.