Neuroendocrine Cell Hyperplasia

Neuroendocrine cell hyperplasia (confined to the respiratory epithelium) with tumorlets (a proliferation of similar cells with a fibrotic reaction in the surrounding connective tissue) is a rare cause of bronchiolitis obliterans.


Figure 1. HRCT

Note the mosaic pattern with decreased vascularity in the areas of low attenuation on this inspiratory image.



Figure 2


Here, invading the tissue around a bronchiolovascular bundle are nests of small dark cells in a fibrotic stroma. The airway has been obliterated leaving only the artery to define its former location.

Find the pulmonary artery.


Figure 3


At higher magnification, the small tumor cells have uniform nuclei. Mitoses are absent.

Lesions larger than 0.5 cm are defined as carcinoid tumors.

For more on tumorlets, click here.

Figure 4

Neuroendocrine Cell Hyperplasia

In the same case, other airways showed linear hyperplasia of neuroendocrine cells, here stained brown immunohistochemically for serotonin, one of many neuroendocrine markers found in these cells.

To see normal neuroendocrine cells in respiratory epithelium, click here.


Lee J, Brown K, Cool C, Lynch D, Diffuse pulmonary neuroendocrine cell hyperplasia: radiologic and clinical features. J Comput Assist Tomogr 2002; 26:180-184. Abstract

Return to Unknown 8 Discussion

TOP--Rad/Path Home Page





























Pulmonary artery marking bronchiolovascular bundle