RT Journal Article SR Electronic T1 Neuroendocrine tumours—challenges in the diagnosis and classification of pulmonary neuroendocrine tumours JF Journal of Clinical Pathology JO J Clin Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP 862 OP 869 DO 10.1136/jclinpath-2012-201310 VO 66 IS 10 A1 den Bakker, M A A1 Thunnissen, F B J M YR 2013 UL http://jcp.bmj.com/content/66/10/862.abstract AB Pulmonary neuroendocrine (NE) proliferations are a diverse group of disorders which share distinct cytological, architectural and biosynthetic features. Tumours composed of NE cells are dispersed among different tumour categories in the WHO classification of tumours and as such do not conform to a singular group with regards to treatment and prognosis. This is reflected by the highly variable behaviour of NE proliferations, ranging from asymptomatic, for instance in diffuse idiopathic pulmonary NE cell hyperplasia and tumourlets, to highly malignant cancers such as small cell lung cancer and large cell NE carcinoma. In this review NE proliferations are described as distinct entities ranging from low grade lesions to high grade cancers. The differential diagnoses are considered with each of the entries. Finally, mention is made of tumours which may show some NE features.