Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is an extremely rare pulmonary disorder where there is a proliferation of neuroendocrine cells within the lung. It is however recognised with increasing frequency.

Epidemiology

There may be an increased female predilection ³. Most patients tend to be non-smokers.

Clinical presentation

Most are asymptomatic, where discovery is made incidentally on thoracic imaging for an unrelated reason. Some, however, may present with symptoms such as an insidious cough or a slowly progressive dyspnoea ⁷.

Pathology

It is characterised by a generalised proliferation of scattered single cells, small nodules or linear proliferations of pulmonary neuroendocrine cells (enterochromaffin cells, "Kulchitsky cells") ⁹. It is sometimes considered to be a precursor forto pulmonary carcinoid tumours.

Radiographic features

CT/HRCT chest

Various features have described each of which are non specific-specific on their own. These include:

• small lung nodules: considered a generally frequent feature ^3-4 
• ground-glass changes ³
• mosaic perfusion pattern ^6-7: due to air trapping
• bronchial wall thickening ⁷ 
• mucus plugging
• bronchiectasis ^3,7

Treatment and prognosis

The rarity of the condition poses some clinical challenge on establishing treatment and assessing prognosis. Limited studies suggest that the condition can have a variable prognosis ranging from clinical improvement to being stable to clinical deterioration (rare ⁵). Various treatment strategies have been described which include systemic and inhaled corticosteroids, bronchodilators, and lung resection.

History and etymology

The first clinical series of six cases describing DIPNECH was published by Aguayo et al in 1992.