INTRODUCTION: DIPNECH is a rare pulmonary disease that has an insidious presentation that may lead to delayed diagnosis. We describe a case of DIPNECH in a young women with a two year history of cough and mild dyspnea.
CASE PRESENTATION: A 37 year-old woman was referred to our pulmonary clinic for evaluation of chronic non productive cough and abnormal CT scan showing a mosaic pattern. Her cough and mild dyspnea was persistent for two and a half years. The patient’s medical history was significant for GERD, eczema and asthma diagnosed after joining the military four years prior. Her medications included inhaled budesonide with formoterol, loratadine, and esomeprazol. She denied alcohol, tobacco and illicit drugs. She is currently active in the US Army and states she was deployed to the Middle East for two years where she was exposed to burn pits. On physical exam her vitals signs were normal. Pulmonary exam demonstrated bilateral wheezing. The results of the initial laboratory tests were normal. Echocardiogram was unremarkable. Pulmonary Function test demonstrate a borderline obstructive pulmonary defect with air trapping and airflow reversibility. These were unchanged from PFT’s prior to initiating budesonide/formoterol. A bronchoscopy with BAL performed six months prior demonstrated no endobronchial lesions. The BAL cultures and cytology were negative. A repeat high resolution CT scan revealed a mosaic pattern more pronounced on the expiratory images with multiple bilateral sub-centimeter nodules. The patient was referred for surgical lung biopsy which showed advanced chronic small airways disease with evidence of constrictive bronchiolitis. Numerous carcinoid tumorlets along with patchy neuroendocrine hyperplasia of airways were present.
DISCUSSION: DIPNECH is a rare primary lung disorder. In 1999, was included as an entity in the World Health Organization (WHO) classification of lung tumors and by then fully recognized and named accordingly. The cardinal pathophysiologic change is progressive narrowing and eventual obstruction of the small airways as a consequence of obliterative bronchiolitis and excessive intraluminal proliferation of the pulmonary endocrine cell. The pathologic change of airway obstruction dictates the common features in clinical presentation, pulmonary function test, and radiologic examination. Clinical presentation is often insidious, with slow onset of dry cough and breathlessness; however, some patients are asymptomatic. While clinical signs are minimal, PFTs tend to show variably severe obstructive or mixed obstructive and restrictive patterns, but may be normal in a minority of cases. The most consistent changes on high-resolution chest CT included thickening of bronchiolar walls and mosaic pattern of air trapping presumably caused by airway obstruction. Nodules are occasionally detected on chest CT. The nodules usually represent tumorlets or peripheral typical carcinoid tumors commonly associated with DIPNECH. Follow-up without treatment may be a reasonable first course of action. However, a trial of steroid therapy is warranted if pulmonary function indices deteriorate. Patients generally have slowly progressive disease over many years with a very good long term prognosis; however, occasional patients develop more rapidly deteriorating airway obstruction with extreme bronchiolar obliteration and may even die of the disease [1, 2, 3].
CONCLUSIONS: We report an extremely rare case of DIPNECH. Clinical diagnosis is extremely challenging and often delayed for many years after initial presentation due to the insidious clinical course, non-characteristic presentations, and lack of effective noninvasive diagnostic tests. Pathologic evaluation of lung tissue is the gold standard in making a definitive diagnosis.
Reference #1  Y. Ge, M.A. Eltorky: Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia. Ann. Diagn. Pathol. 11 (2007) 122-126.
Reference #2  Davies SJ, Gosney JR: Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia: an under-recognised spectrum of disease. Thorax 2007, 248-252.
Reference #3  C. Lim, Stanford: Diffuse idiopathic pulmonary endocrine cell hyperplasia. Pathology international 2010; 538-541.
DISCLOSURE: The following authors have nothing to disclose: Luis Chug, Heath Latham
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