Clinical Pearls & Morning Reports

Posted by Carla Rothaus

Published February 10, 2021


What are some of the features of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia?

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare entity characterized by the generalized proliferation of pulmonary neuroendocrine cells. Read the NEJM Case Records of the Massachusetts General Hospital here.

Clinical Pearls

Q: Does DIPNECH mainly affect men or women?

A: DIPNECH predominantly affects middle-aged women with no clear association with smoking exposure. Common presenting symptoms include cough and dyspnea, but in approximately 50% of patients, no symptoms develop and the disease is detected incidentally.

Q: Is DIPNECH an aggressive condition?

A: DIPNECH is a clinically indolent premalignant condition that may progress to form localized tumorlets, invasive carcinoid tumors, or both, although the time from disease onset to malignant transformation remains unknown. In one case series, approximately 40% of patients with DIPNECH were found to have synchronous carcinoid tumors.

Morning Report Questions

Q: What are some of the features of DIPNECH?

A: The entity is associated with peribronchiolar fibrosis that leads to a constrictive obliterative bronchiolitis. Dyspnea, a history of wheezing, an obstructive or a mixed obstructive–restrictive pattern on pulmonary-function tests, air trapping, and multiple small lung nodules on imaging are compatible with a diagnosis of DIPNECH. Immunohistochemical staining that is positive for synaptophysin and chromogranin A in the carcinoid tumors and tumorlets, as well as in the microscopical foci of neuroendocrine cell hyperplasia, is consistent with DIPNECH. 

Q: Do all patients with DIONECH require treatment?

A: For asymptomatic patients, observation is commonly recommended, given the long natural history of the disease. Among symptomatic patients, somatostatin analogues, mammalian target of rapamycin inhibitors, and bilateral lung transplantation have been investigated, but data regarding outcomes associated with these strategies are largely limited to small retrospective studies. Nevertheless, several case series have suggested that the use of somatostatin analogues leads to improvements in symptoms and the FEV1 among patients with DIPNECH, and current recommendations from the National Comprehensive Cancer Network are to consider these agents in symptomatic patients.

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