[Spontaneous remission of follicular bronchiolitis with nonspecific interstitial pneumonia: A case report and literature review].

A 41-year-old female patient was admitted in Department of Respiratory and Critical Care Medicine, Peking University Third Hospital because of having cough for a year. Multiple subpleural ground grass and solid nodules could be seen on her CT scan. Four months before admission, she began to experience dry mouth and eyes, blurred vision, finger joints pain, muscle pain and weakness in both lower limbs and weight loss. At the time of admission, the patient's vital signs were normal, no skin rash was seen, breath sounds in both lungs were clear, no rales or wheeze, no deformities in her hands, no redness, swelling, or tenderness in the joints. There was no edema in both lower limbs. Some lab examinations were performed. Tumor markers including squamous cell carcinoma (SCC) antigen, neuron-specific enolase (NSE), carcinoembryonic antigen (CEA), Cyfra21-1, pro-gastrin-releasing peptide (proGRP), carbohydrate antigen 125 (CA125) and carbohydrate antigen 199 (CA199) were all normal. The antinuclear antibody, rheumatoid factor, antineutrophil cytoplasmic antibody, anti-dsDNA antibody, anti-Sm antibody, anti-SSA/SSB antibody, anti-ribonucleoprotein (RNP) antibody, anti-Jo-1 antibody, anti-SCL-70 antibody and anti-ribosomal antibody were all negative. The blood IgG level was normal. The blood fungal β-1.3-D glucose, aspergillus galactomannan antigen, sputum bacterial and fungal culture, and sputum smear test for acid-fast staining were all negative. Lung function was normal. Bronchoscopy showed the airways and mucosa were normal. To clarify the diagnosis, she underwent thoracoscopic lung biopsy, the histopathology revealed follicular bronchiolitis (FB) with nonspecific interstitial pneumonia (NSIP). She did not receive any treatment and after 7 months, the lung opacities were spontaneously resolved. After 7 years of follow-up, the opacities in her lung did not relapse. To improve the understanding of FB, a literature research was performed with "follicular bronchiolitis" as the key word in Wanfang, PubMed and Ovid Database. The time interval was from January 2000 to December 2018. Relative articles were retrieved and clinical treatments and prognosis of FB were analyzed. Eighteen articles concerning FB with complete records were included in the literature review. A total of 51 adult patients with FB were reported, including 18 primary FB and 33 secondary FB, and autoimmune disease was the most common underlying cause. Forty-one (80.4%) patients were prescribed with corticosteroids and/or immunosuppressive agents, 6 (11.8%) patients were treated with anti-infective, 5 (9.8%) patients did not receive any treatment. The longest follow-up period was 107 months. Among the 5 patients without any treatment, 1 patients died of metastatic melanoma, the lung opacities were unchanged in 1 patient and getting severe in 3 patients. In conclusion, FB is a rare disease, the treatment and prognosis are controversial. Corticosteroid and immunosuppressive agents could be effective. This case report suggests the possibility of spontaneous remission of FB.