[Anatomopathology of lung carcinoma: classic data and new concepts]

The classification of lung cancers is based on that defined by the WHO in 1982. Electron microscopy and immunohistochemistry have put some tumours (carcinoids and small cell carcinomas) in the same neuroendocrine differentiation family. Between the two ends of the differentiation spectrum are tumours of intermediate malignancy, such as well-differentiated neuroendocrine carcinomas or atypical carcinoids. Numerous proposals of classification have been published, and in particular some large cell lung cancers have been included in the neuroendocrine carcinoma group. The type of lung cancer is sometimes difficult to diagnose on biopsy material; it is easier to determine with precision on surgical specimens. TNM evaluation is based on detailed macroscopic evaluation of local and regional lymph node invasion by the tumour.