Abstract Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is being recognized with increasing frequency. Diagnostic and treatment information is limited. A systematic review is presented, focusing on patient demographics, clinical presentation, diagnosis, treatment options, and outcomes. A systematic electronic literature search was conducted for adult DIPNECH cases reported in the English literature during the past 6 years. Twenty-four DIPNECH cases were identified. Another case from our institution is contributed. Women represent 92% (23 of 25). Mean age at diagnosis was 58 years (range, 36–76 yr). Most were nonsmokers (16 of 24). Symptoms included cough (71%), dyspnea (63%), and wheezing (25%) occurring days to years before diagnosis. Pulmonary function testing showed obstructive ventilatory disease in 54%. Lung nodules were seen in 15 patients (63%), ground-glass attenuation in 7 patients (29%), and bronchiectasis in 5 patients (21%). Histological confirmation required surgical lung biopsy for 88%; however, transbronchial biopsies alone were diagnostic in three patients. Treatments strategies included systemic and inhaled corticosteroids, bronchodilators, and lung resection. Available follow-up data in 17 patients showed 6 clinically improved, 7 who remained stable, and 4 clinically deteriorated. The majority of patients presenting with DIPNECH are middle-aged females with symptoms of cough and dyspnea; obstructive abnormalities on pulmonary function testing; and radiographic imaging showing pulmonary nodules, ground-glass attenuation, and bronchiectasis. In general, the clinical course remains stable; however, progression to respiratory failure does occur. Long-term follow-up and treatment remains incomplete. Establishment of a national multicenter DIPNECH registry would allow formulation of optimal evidence-based guidelines for management of these patients.