Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia: A Clinical Case

A Rare Case of Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia: A Case Report

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare pulmonary disease characterized by the diffuse proliferation of neuroendocrine cells in the bronchial epithelium. It is considered a preinvasive precursor to carcinoid tumors and usually presents with obstructive symptoms. We present the case of a 71-year-old female, non-smoker, with a past medical history of asthma, osteoarthritis, allergic rhinitis, and hyperlipidemia who was referred to the pulmonology clinic in view of incidental chest CT findings of multiple pulmonary nodules. Physical examination and labs were unremarkable. CT of the chest showed scattered multiple noncalcified pulmonary nodules with a 10 mm dominant nodule in the inferior right middle lobe and several subcentimeter hypodensities in the left and right lobes of the lung. A PET scan confirmed the CT findings along with no abnormal hypermetabolic activity to suggest malignancy. The patient was followed up in the pulmonology clinic at six months, 12 months, and then 18 months. At 18 months owing to a slight increase in the size of the largest lung nodule, a CT-guided biopsy done was conclusive of a carcinoid. The tumor cells were positive for synaptophysin, chromogranin, insulinoma-associated protein 1 (INSM-1), and thyroid transcription factor 1 (TTF-1). The Ki-67 (Keil) index was <1%. A video-assisted thoracic surgery with right middle lobectomy along with mediastinal lymph node dissection was then done, and the patient was found to have stage pT1aN0 typical carcinoid tumor (1.0 cm), with multiple carcinoid tumors and neuroendocrine hyperplasia, consistent with DIPNECH. She has been under clinical follow-up for over three years at present and continues to be asymptomatic with complete remission following surgery. DIPNECH primarily affects middle-aged, non-smoking females who present with cough and dyspnea, and diagnosis is often delayed due to clinical features overlapping with those of obstructive lung disease. Imaging shows lung nodules, ground-glass opacities, and/or mosaic attenuation. Due to the rarity of the conditions, there are no established clinical trials, and therefore, there is a need to establish guidelines.

Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia: A Blanked Out Pulmonary Neuroendocrine Tumor

Introduction

Lung neuroendocrine tumors (NETs) are a rare type of pulmonary tumor and represent approximately 2% of all lung cancers. The prevalence of lung NETs is increasing, which may be due to improved diagnostic techniques for asymptomatic tumors. Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare and underdiagnosed disease that falls under the spectrum of NETs.

Case Presentation

We presented a case of a 59-year-old male who presented with severe coughing spells, flushing, and diarrhea. His computed tomography scan showed innumerable pulmonary nodules and irregular nodular opacities throughout the lungs. He underwent a left upper lobe wedge resection and was eventually diagnosed with neuroendocrine tumorlets via immunohistochemical stains. He was started on a trial of octreotide and reported significant improvement in symptoms after 1 month.

Conclusion

DIPNECH is a rare preinvasive lesion characterized by the abnormal proliferation of pulmonary neuroendocrine cells. Patients with DIPNECH can present initially with respiratory symptoms, while other cases are discovered incidentally during the workup of different conditions. Definitive diagnosis of DIPNECH requires histopathological examination of lung tissue. There is limited evidence on DIPNECH management, and an individualized approach is currently advised.

Rare Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia (DIPNECH) Finding in a 9/11 World Trade Center Survivor: A Case Report

Bronchial carcinoid tumors represent a relatively uncommon category within lung neoplasms, originating from neuroendocrine cells. The exact cause of these pulmonary tumors remains not fully understood. Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is characterized by widespread hyperplasia of these neuroendocrine cells, essential for regulating air and blood flow in response to stimuli such as hypoxia, dyspnea, and chronic obstructive pulmonary disease (COPD). The prognosis for bronchial carcinoid tumors hinges on factors such as grade and stage, with lung resection being the preferred treatment. A chest computed tomography (CT) scan unveiled diffuse bilateral pulmonary nodules with ground-glass opacities, leading to a right video-assisted thoracoscopic surgery (VATS) wedge resection. Immunohistochemical examination confirmed neuroendocrine differentiation, describing a lung wedge measuring 9 × 4 × 1.5 cm with spongy parenchyma and scattered white nodules.