Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) masquerading as metastatic carcinoma with multiple pulmonary deposits.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare pulmonary disorder presenting with multiple pulmonary nodules in association with a typical mosaic perfusion pattern on computed tomography. In this case, the absence of mosaic perfusion led to an erroneous initial diagnosis of pulmonary metastases from an unknown primary malignancy. This illustrates the importance of considering differential diagnoses when presented with imaging findings compatible with pulmonary metastases from an unknown primary, and highlights the importance of histopathologic confirmation in such cases.