Abstract Introduction Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia (DIPNECH) is an extremely rare condition with only about 200-400 cases reported in literature worldwide since 1992. It is characterized by diffuse proliferation of pulmonary neuroendocrine cells, airway obstruction, mosaic attenuation/air trapping on chest CT, and symptoms including cough, dyspnea, and wheezing. Radiographs most often show numerous bilateral small ( 5-10 mm) nodules. Here, we present a case of DIPNECH, outlining the diagnostic dilemma and treatment approaches for the patient. Case Summary The patient is a 60 year old female lifetime non smoker who presented to emergency department (ED) with worsening of shortness of breathing (SOB) recently. She has history of chronic intermittent dry cough and shortness of breath for at least the past 30 years but never followed up with any physician. In the ED, chest CT revealed randomly and perilymphatically distributed bilateral noncalcified pleural based pulmonary nodules, associated mosaic lung attenuation suggestive of air trapping, and minimal rightward tracheal deviation (figure 1). Pulmonary function testing (PFT) revealed a mixed obstructive and restrictive defect, with FEV1/FVC 70%. The patient subsequently underwent fine needle aspiration and CT guided lung biopsy. FNA of a right pulmonary nodule revealed a well differentiated neuroendocrine tumor. She was initiated on lanreotide, a somatostatin analogue, to which she responded well, remaining in remission for 5 years. A follow up CT scan revealed unchanged pulmonary nodules but new mediastinal lymph node avidity concerning for disease progression. Further treatment options, including everolimus (an mTOR inhibitor), were then discussed. Discussion DIPNECH predominantly affects middle aged to older women, mostly non smokers. PFTs demonstrate a primarily obstructive pattern (↓FEV1/FVC, ↑residual volume, air trapping), occasionally with reduced DLCO. Radiographic features include mosaic attenuation/air trapping, numerous bilateral pulmonary nodules 5-10 mm, and bronchial wall thickening. Our patient exhibited all the above, including multiple pulmonary tumorlets too small to qualify as bronchial carcinoid tumors. Additionally, she had no history of smoking, tuberculosis exposure, acute/subacute symptoms (fever, chills, granulomatous inflammation), malignancy, rash, joint involvement, lymphadenopathy, or connective tissue disease—effectively ruling out COPD, tuberculosis, hypersensitivity pneumonitis, metastasis, sarcoidosis, and connective tissue diseases. Finally, the patient achieved remission with lanreotide—a somatostatin analogue, which is the standard treatment for DIPNECH. Conclusion DIPNECH is a rare and underdiagnosed condition often misdiagnosed as asthma or COPD. Definitive diagnosis requires clinical suspicion, characteristic radiographic findings, and histologic sampling. Physicians should maintain high suspicion, as it can progress to carcinoid tumor or respiratory failure. This abstract is funded by: None
Akter et al. (Fri,) studied this question.