TOPIC: Lung Cancer TYPE: Medical Student/Resident Case Reports INTRODUCTION: Chronic cough is one of the most common symptoms for which outpatient care is sought. The differential diagnosis is broad, and many patients undergo extensive evaluation. We here report a rare case of chronic cough with progressive dyspnea due to Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia( DIPNECH), followed by a brief literature review of DIPNECH. CASE PRESENTATION: 70-year-old female, non smoker, history of Crohn's disease presented to the Pulmonology clinic in 2005 with cough and shortness of breath. PFT's showed restrictive pattern. CT scan showed multiple bilateral pulmonary nodules. Bronchoscopy could not identify cause. On periodic CT, lung nodules remained stable. In the meantime, she continued to have chronic cough and progressively worsening shortness of breath. She received multiple trials of steroids, antibiotics, and inhalers with mild improvement. Repeat PFT's now showed severe obstructive disease. Her coughing spells made it difficult to perform on PFTs. She underwent repeat bronchoscopy with extensive testing, including bacterial, fungal, malignancy, and autoimmune causes of her symptoms, all of which came back negative. The working diagnosis was necrobiotic nodules secondary to her Crohn's disease vs. Asthma. She was put on a prolonged steroid course and developed severe side effects like muscle weakness, mood changes, tremors and worsening kidney function. The patient was hesitant to go back on steroids. She had suffered for 17 years. A trial of steroid-sparing medication CellCept was considered. However, before committing the patient to these, a wedge biopsy of the pulmonary nodule was performed and revealed neuroendocrine cells that stained positive for synaptophysin, chromogranin, and CD56.8 confirming the diagnosis of DIPNECH. The patient was subsequently referred to oncology and started on Octreotide infusions causing significant improvement in symptoms. DISCUSSION: DIPNECH is a rare condition that is becoming increasingly recognized. It is typically characterized by an insidious onset with chronic nonproductive cough, exertional dyspnoea, and wheezing, spuriously attributed to Asthma, chronic obstructive pulmonary disease, or GERD. Indeed, the diagnosis of DIPNECH is usually made several years after the onset of clinical symptoms, often following the incidental discovery of a lung nodule (or nodules) on imaging, usually computed tomography (CT). It is characterized histologically by a diffuse, bronchiolo-centric proliferation of neuroendocrine cells at the periphery of the lung, radiologically by ground-glass opacity, mosaic attenuation with air trapping, bronchial wall thickening, and pulmonary nodules and, Clinically by symptoms of airflow limitation. CONCLUSIONS: We hope this case can increase awareness of DIPNECH among clinicians as patients may otherwise be misdiagnosed and undergo unnecessary treatments or procedures causing permanent harm. REFERENCE #1: Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia 1Margaret Wei, MD and 2Mehri Manouchehr-Pour CLINICAL VIGNETTE1UCLA Department of Medicine2UC Riverside Department of Cell, Molecular, and Developmental Biology DISCLOSURES: No relevant relationships by Venkatkiran Kanchustambham, source=Web Response No relevant relationships by Swetha Saladi, source=Web Response No relevant relationships by Khurram Shafique, source=Web Response No relevant relationships by Vinita Vaidya, source=Web Response