DIPNECH: Association Between Histopathology and Clinical Presentation.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare disorder which can be an incidental finding in imaging tests performed during the investigation of another condition, or is the final diagnosis in patients evaluated for chronic obstructive complaints. To explore the possible association between specific histopathology features and the mode of clinical presentation, we retrieved the clinical, functional, radiological, and pathological data of all 13 patients diagnosed with DIPNECH at our Institution over a 14-year period (2000-2014). As compared to patients with incidental disease (6/13, 46 %), patients with symptomatic disease were younger [mean (SD): 57.7 vs. 68.7 years, p = 0.046], were more likely to have mosaic attenuation (100 vs. 0 %, p = 0.001) and small multiple nodules (100 vs. 17 %, p = 0.005) at CT, and showed a significantly higher number of foci of linear neuroendocrine proliferation [median (IQR): 28 (13-37) vs. 6 (5-13), p = 0.018] and of tumorlets [median (IQR): 10 (8-20) vs. 1 (1-1), p = 0.002] at histology. Incidental disease was found in association with pulmonary adenocarcinoma in five out of six patients (83.3 %). The results of our study provide preliminary evidence that symptomatic patients with DIPNECH represent a specific subset characterized by younger age and a higher burden of foci of neuroendocrine proliferation.