January 2024

Carcinoid tumour with Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH)

January 2024

Dr Faisal Ashraf, Radiology Registrar, University Hospitals of North Midlands.

Dr Alim Yucel-Finn, Cardiothoracic Radiology Consultant, University Hospitals of North Midlands.

Case history

67-year-old female presents with significant weight loss.  Initially investigated with a CT abdomen and pelvis which identified multiple lung nodules at the lung bases. Subsequent CT thorax demonstrated several bilateral nodules with areas of air trapping. A cluster of larger nodules in the left lower lobe were seen and found to be avid on both FDG -PET CT and DOTA-PET CT.   The patient went on to have a VATS with left lower lobectomy, histology confirmed a diagnosis of carcinoid tumour with features of DIPNECH.


Neuroendocrine cells are usually found in respiratory mucosa and have important functions in epithelial repair and detection of hypoxia. The hyperplasia of these cells can be either reactive which is thought to be secondary to chronic hypoxia and follows a benign path or can be idiopathic (DIPNECH) which is considered pre-invasive and can be associated with the formation of carcinoid tumours. The disease is rare, under recognised and almost exclusively seen in middle aged or elderly females. The clinical presentation can be variable and usually asymptomatic. When symptomatic patients usually report an unrelenting cough, dyspnoea and wheeze which is sometimes misattributed to asthma.

The diagnosis of DIPNECH can be suggested on imaging with typical features including multiple, often bilateral tiny (<5 mm) broncho-centric nodules with bronchial wall thickening as well as regional air trapping/ mosaicism.  The mosaicism is seen as a result of peptide secretion from the micronodules causing a constrictive bronchiolitis.  Definitive diagnosis however can only be established on histological examination.

DIPNECH seen in isolation has a generally favourable prognosis with a 5-year survival of 83% and most cases are managed conservatively. In those who are symptomatic and with greater respiratory impairment medical management with steroids, interferon-α and chemotherapy agents can be considered. In the minority of patients not responding to medical management lung transplantation has been offered in selected patients.  Continued imaging follow-up of patients with DIPNECH is recommended to assess for the development of carcinoid tumours.