Isolated mosaic pattern due to bronchiolitis in non-transplant patients: Etiology in 60 cases

The Aim: was to identify associated diseases with mosaic pattern in HRCT in non-transplanted patients due to bronchiolar disease. Methods Retrospective study of 60 consecutive patients clinically diagnosed to have a bronchiolar disease based on the presence of mosaic perfusion pattern with air trapping in HRCT. Results: The median age was 55±17 years; 57 were women (95%) and 16 (27%) had a smoking history. Dyspnea was the most common symptom, present in 50 (83%). Relevant exposures were present in 25 cases (42%): birds or molds or both in 12, occupational in 2. Crackles were heard in 12 (20%), and wheezes or squawks in 13 (22%). FVC was 72±19%, FEV 1 was 64±23%, FEV 1 /FVC was 0.69±0.15.The most common ventilator defect were obstructive (40%), and nonspecific, n=22 (38).Surgical lung biopsy was done in 20 (33%). Clinical final diagnoses were: Connective tissue diseases: 26 (43%)-rheumatoid arthritis in 16, others in 10 (4 systemic sclerosis). The second most common cause was hypersensitivity pneumonitis, with 9 (15%) of the cases. The third most common cause was post-infectious bronchiolitis, in 8 (13%). Inb3 cases (5%) the final diagnosis was idiopathic constrictive bronchiolitis. Etiology was undefined in 4. Remaining causes included several conditions. Conclusions: Many causes are associated with mosaic pattern due to bronchiolar disease. Connective tissue diseases, HP and post-infectious must be always considered. Many causes must be excluded before diagnosis of idiopathic constrictive.