Morphological and Immunohistochemical Features of Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia: Aguayo – Miller Disease

by, Prof. Dr. Lutfi ALIA

Abstract

Difuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare pulmonary disorder that is characterized hyperplasia of bronchiolar and bronchial pulmonary neuroendocrine cells. Te hyperplasia of neuroendocrine cells can be primary or reactive. In the WHO – IASLP classifcation of lung tumours (1999, 2004, 2005, 2015), DIPNECH is considered a preneoplastic lesion in the spectrum of pulmonary tumours. According to the WHO classifcation, the defnition of DIPNECH is purely histological. Te histological appearance of DIPNECH within the lungs takes many forms. It may comprise a difuse hyperplasia of scattered neuroendocrine cells, small nodules (neuroendocrine bodies), or a linear proliferation in alveolar ducts and alveols. Tese proliferations are superfcial to the basement membrane and confned to the bronchial and bronchiolar epithelium. When there is extension beyond the basement membrane, the neuroendocrine cell proliferations in the multiple nodules < 5 mm diameter are termed tumourlets, but where the tumourlets have > 5 mm diameter are classifed carcinoid tumours. Te DIPNECH was initially described in 1992 by Aguayo et al., who reported six non-smoking patients with cough, exertional dyspnea, wheezing, less frequently 7 MEDICUS / NO. 3, 2020 hemoptysis and a mixed obstructive/restrictive defect on pulmonary function tests. In the Aguayo – Miller disease, the DIPNECH is a primary proliferation and is associated with tumourlets and carcinoid and with obstructive bronchiolitis. Tis disease has a predilection for nonsmoking middle-aged women (female to male ratio it’s approximately 10:1) In this study we present a 62-year-old, non-smoker woman, presented with respiratory symptoms ascribable to DIPNECH. Afer surgery, the morphological study of lung specimens, conferme the DIPNECH, multiple tumourlets, one peripheral carcinoid and obliterative bronchiolitis in the right middle pulmonary lobe.