An Unexpected Diagnosis of Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia

Abstract

SESSION TITLE: Lung Pathology 2 SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare, poorly understood disease. First diagnosed in 1992, DIPNECH has since been recognized by the World Health Organization in 2004 as a precursor lesion to pulmonary carcinoid tumors1. If symptomatic, patients may present with an insidious cough, dyspnea, and/or wheezing. CASE PRESENTATION: A 68-year-old female, former smoker, Sjogren’s disease on hydroxychloroquine, gastric lymphoma treated with chemotherapy in 2013, Mucosa-Associated Lymphoid Tissue lymphoma of the left parotid gland treated with radiation in 2000, history of multiple non-necrotizing granulomatous lung nodules presents to pulmonary clinic. Her Computerized Tomography (CT) scan of the chest revealed multiple enlarging peribronchovascular nodules bilaterally with the largest measured at 3x5 cm in the lingula. Other findings included mosaicism and bronchial wall thickening (Fig 1). She underwent transbronchial biopsy of the lingula and pathology revealed carcinoid tumor. Patient then underwent wedge excision of the lingular mass by cardiothoracic surgery. Subsequent pathology revealed multiple scattered neuroendocrine cell proliferations (tumorlets) in the peribronchiolar areas which stained positive for synaptophysin and chromogranin, supporting a diagnosis of DIPNECH (Fig 2). With no additional immediate interventions planned, she will be monitored with repeat imaging in a few months. DISCUSSION: DIPNECH is associated with radiographic changes of pulmonary nodules, mosaic attenuation, and bronchiectasis, which were all seen in our patient1. Nassar et al demonstrated a higher diagnostic yield with surgical lung biopsies (gold standard) over transbronchial biopsies2. The adult lung has a limited number of neuroendocrine cells and DIPNECH may lead to proliferation of these cells superficial to the basement membrane of bronchiolar epithelium or as tumorlets beyond the basement membrane1. These proliferations may cause obstructive airway disease and lead to symptoms of cough, dyspnea, or wheezing. Our patient had baseline mild dyspnea on exertion and obstructive pattern on pulmonary function tests, potentially from DIPNECH. CONCLUSIONS: Although a precursor lesion to pulmonary carcinoid tumor, DIPNECH has no consensus treatments. Symptom management may be achieved with steroid therapies or somatostatin analogues while patients are closely observed1. Our patient, given her history of malignancy, will be closely monitored by both pulmonary and oncology services. Reference #1: P. Mitchell, M. Kennedy and M. Henry, “A Case of DIPNECH and Review of the Current Literature,” Open Journal of Respiratory Diseases, Vol. 3 No. 2, 2013, pp. 68-72. Reference #2: A. Nasser, D. Jaroszewski, R. Helmers and T. Colby, “Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia: A Systematic Overview,” American Journal of Respiratory and Critical Care Medicine, Vol. 184, No. 18-16, 2011, pp. 8-16 DISCLOSURE: The following authors have nothing to disclose: Asem Qadeer, Prachi Vishwasrao, Keith Sweeney, Muhammad Perwaiz No Product/Research Disclosure Information