Follicular bronchiolitis: a rare cause of bronchiolitis obliterans syndrome after lung transplantation: a case report

[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.

Follicular Bronchiolitis: Two Cases with Varying Clinical and Radiological Presentation

Follicular bronchiolitis (FB) is a rare bronchiolar disorder associated with hyperplasia of the bronchial-associated lymphoid tissue (BALT). It is characterized by the development of lymphoid follicles with germinal centers in the walls of small airways. It falls under the category of lymphoproliferative pulmonary diseases (LPDs) and commonly occurs in relation to connective tissue disease, immunodeficiency, infections, interstitial lung disease (ILD), and inflammatory airway diseases. Computerized tomography (CT) findings include centrilobular nodules with patchy ground glass infiltrate, tree-in-bud findings, and air trapping. It can very rarely present as diffuse cystic lung disease. We present two cases of FB. The first case is associated with Human Immunodeficiency Virus (HIV) infection and asthma with diffuse cystic changes on the CT. The second case is associated with reactive airway disease and gastroesophageal reflux disease (GERD) with the classic centrilobular nodules and ground glass opacities on the CT.

A new classification system for chronic lung allograft dysfunction

Although survival after lung transplantation has improved significantly during the last decade, chronic rejection is thought to be the major cause of late mortality. The physiologic hallmark of chronic rejection has been a persistent fall in forced expiratory volume in 1 second associated with an obstructive ventilatory defect, for which the term bronchiolitis obliterans syndrome (BOS) was defined to allow a uniformity of description and grading of severity throughout the world. Although BOS was generally thought to be irreversible, recent evidence suggests that some patients with BOS may respond to azithromycin with > 10% improvement in their forced expiratory volume in 1 second. In addition, a restrictive form of chronic rejection has recently been described that does not fit the strict definition of BOS as an obstructive defect. Hence, the term chronic lung allograft dysfunction (CLAD) has been introduced to cover all forms of graft dysfunction, but CLAD has yet to be defined. We propose a definition of CLAD and a flow chart that may facilitate recognition of the different phenotypes of CLAD that can complicate the clinical course of lung transplant recipients.

Survival determinants in lung transplant patients with chronic allograft dysfunction

BACKGROUND

Chronic lung allograft dysfunction (CLAD) remains the leading cause of mortality after lung transplantation.

METHODS

In this retrospective single-center study, we aimed to identify different phenotypes of and risk factors for mortality after CLAD diagnosis using univariate and multivariate Cox proportional hazard survival regression analysis.

RESULTS

CLAD was diagnosed in 71 of 294 patients (24.2%) at 30.9±22.8 months after transplantation. Pulmonary function was obstructive in 51 (71.8%) of the CLAD patients, restrictive in 20 (28.2%) patients, of whom 17 had persistent parenchymal infiltrates on pulmonary computer tomography (CAT) scan. In univariate analysis, previous development of neutrophilic reversible allograft dysfunction (NRAD, P=0.012) and a restrictive pulmonary function (P=0.0024) were associated with a worse survival, whereas there was a strong trend for early development of CLAD and persistent parenchymal infiltrates on CAT scan (P=0.067 and 0.056, respectively). In multivariate analysis, early development of CLAD (P=0.0067), previous development of NRAD (P=0.0016), and a restrictive pulmonary function pattern (P=0.0005) or persistent parenchymal infiltrates on CAT scan (P=0.0043) remained significant.

CONCLUSION

Although most CLAD patients develop an obstructive pulmonary function, 28% develop a restrictive pulmonary function, compatible with the recently defined restrictive allograft syndrome phenotype. Early-onset CLAD, previous development of NRAD, and the development of restrictive allograft syndrome are associated with worse survival after CLAD has been diagnosed.

Pathology of small airways disease

CONTEXT

The term small airways disease encompasses a generally poorly understood group of lung diseases that may arise primarily within the small airways or secondarily from diseases primarily affecting the bronchi or lung parenchyma. Their histology may be confusing; however, because treatments and prognoses vary, correct pathologic diagnosis is important.

OBJECTIVE

To present a nonexhaustive review of the pathology of primary and secondary small airways diseases, including small airways disease related to tobacco; to various other exposures, including mineral dusts; to diseases involving other areas of the lung with secondary bronchiolar involvement; and to recently described bronchiolitic disorders.

DATA SOURCES

Current literature is reviewed.

CONCLUSIONS

Small airways diseases include a wide variety of diseases of which the pathologist must consider. Uncommon conditions such as diffuse idiopathic neuroendocrine cell hyperplasia and diffuse panbronchiolitis may show relatively specific diagnostic features histologically; however, most small airways diseases exhibit nonspecific histologic features. Conditions not considered primary pulmonary diseases, such as collagen vascular diseases, bone marrow transplantation, and inflammatory bowel disease, must also be considered in patients with small airways changes histologically. Clinical and radiologic correlation is important for obtaining the best possible diagnosis.

Small Airways Disease

Small airways diseases are best defined pathologically as a diverse group of conditions that primarily involve bronchioles and acartilagenous airways 2 mm or less in diameter, which include membranous bronchioles, respiratory bronchioles, and alveolar ducts. Small airways can be involved with disease primarily or secondarily. The concept of small airways disease varies among specialties, with clinicians generally considering them in terms of terminal airway changes causing airflow obstruction, radiologists considering them in the context of direct signs and indirect signs identified on high-resolution computed tomography scans, and pathologists evaluating them based entirely or almost entirely on the histologic changes present in the bronchioles, with or without associated changes involving bronchi and alveoli. The histologic features of small airways diseases may be confusing because they overlap. There may be incomplete assessment of the histologic process with limited biopsy. Other disease processes may occur along with a small airways disease, and may obscure or confound its histologic features. This article focuses on the histologic changes diagnostic of a variety of primary and secondary small airways diseases. Because the histologic features involve bronchioles, gross findings are often minimal and/or nonspecific. The article provides a nonexhaustive examination of conditions and diseases involving the small airways, focusing on the microscopic features, with emphasis on the limitations of histologic diagnosis and differential diagnosis.