Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH)

Case contributed by Stefan Tigges
Diagnosis probable

Presentation

Cough, shortness of breath. History of asthma.

Patient Data

Age: 45 years
Gender: Female

Lungs are clear, no pleural effusion, normal cardiomediastinal sillhoutte.

Innumerable bilateral <5 mm nodules are present with mosaic attenuation. Given that the vessels in the darker lung are smaller in size than in the grayer lung, the darker lung is abnormal and the mosaic attenuation likely represents air trapping, but without expiratory views, it is difficult to be absolutely certain. 

Case Discussion

Multiple small lung nodules are most often due to metastatic disease or infection, but in combination with air trapping, diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) must be considered. In contrast to metastases and hematogenous infections that have a random distribution, DIPNECH nodules are centrilobular. Nodules <5 mm in size are considered "tumorlets": nodules >5 mm in size are considered to be carcinoid tumors, so DIPNECH can be considered a pre-invasive condition. Pulmonary neuroendocrine cells are metabolically active and make peptides that produce constrictive bronchiolitis, often resulting in a clinical diagnosis of asthma. On CT, constrictive bronchiolitis leads to mosaic attenuation due to air trapping.

No further diagnostic information such as blood test results or other imaging investigations is available.

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