Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia and Neuroendocrine Hyperplasia of Infancy.

Although incidental reactive pulmonary neuroendocrine cell hyperplasia (PNECH) is seen on biopsy specimens in adults with chronic lung disease, disorders characterized by marked PNECH are rare. Primary hyperplasia of neuroendocrine cells in the lung and obstructive lung disease related to remodeling or physiologic constriction of small airways define diffuse idiopathic neuroendocrine cell hyperplasia (DIPNECH) in the adult and neuroendocrine cell hyperplasia of infancy (NEHI) in children. DIPENCH and NEHI share a similar physiology, typical imaging appearance, and increased neuroendocrine cells on biopsy. However, there are important differences related to the underlying disease mechanisms leading to disparate outcomes.