B72-23 A Rare Case of Silicosis With Overlying Cryptococcosis

Abstract Introduction The differential for diffuse pulmonary nodules is wide and includes immunologic, infectious, or exposure based causes however determining the exact cause in the setting of multiple coinciding factors or exposures may prove difficult. In this case we present a patient incidentally found to have diffuse pulmonary nodules due to coinciding silicosis and pulmonary cryptococcosis, in the setting of seropositive rheumatoid arthritis. Case Report A 43 year old male with a history of recently diagnosed seropositive rheumatoid arthritis (RA) presented to the Emergency Department with polyarticular joint pains in the setting of medication non-adherence. Chest x-ray within the ED incidentally found diffuse miliary opacities in the bilateral lungs. He reported a history of stonecutting marble and granite for 20+ years, but denied history of smoking, wood-burning stoves, sick contacts, or recent travel. He had a temperature of 39.4 °C, a respiratory rate of 20, and an oxygen saturation of 90% on room air. CT scan revealed innumerable, bilateral sub-centimeter non-calcified pulmonary nodules. Lab workup revealed an ESR of 94mm/h, CRP of 161 mg/l, unremarkable primary labs, negative mycobacterial PCR, negative acid fast bacilli (AFB) sputum cultures, negative respiratory cultures, negative HIV and fungal workup (Coccidiodes antibody, Blastomycoses antibody, Histoplasma antigen) except for a positive Cryptococcal serum antigen (CrAg) with a 1:80 titer. Bronchoscopy with broncheoalveolar lavage (BAL) as well as a transbronchial needle biopsy (TNBA) of the lingula were performed. BAL culture was positive for Cryptococcus gattii, while pathology of TNBA revealed rare needle shaped polarizable material with negative grocott methenamine silver and AFB stains. Assessment for central nervous system involvement of Cryptococcus with lumbar puncture and MRI brain were negative. The patient was started on treatment with fluconazole and quit his job in stonecutting. Discussion Silicosis has been associated with increased risk of autoimmune diseases such as rheumatoid arthritis1,2 and atypical infections including tuberculous and non-tuberculous mycobacteria3, however the relationship between silicosis and fungal infections is less established. We describe a rare case demonstrating co-occurence of silicosis with both RA and cryptococcosis. One prior case study reports concurrence of silicoproteinosis with pulmonary cryptococcosis4. Impairment of alveolar macrophage function may mechanistically explain higher susceptibility to fungal infection. A common pathway of immune dysregulation leading to both rheumatoid arthritis and susceptibility to fungal infection in this patient is possible. As such, clinicians should consider cryptococcal infection when evaluating pulmonary nodules in patients with silicosis. This abstract is funded by: None