Table 4 WHO/IASLC Subtypes of neuroendocrine tumours [20]
Classical SCLCSmall round, oval or spindle-shaped cells with scant cytoplasm, ill-defined borders, finely granular nuclear chromatin and absent or inconspicuous nucleoli. High mitotic count. Characteristic crush phenomena due to the soft texture of the tumour and mechanical alterations. Histomorphological grading G1 to G4 not applicable.
Typical/atypical carcinoidUsually less aggressive tumour.
Large cell neuroendocrine tumourProliferation index relevant for classification.
Combined SCLCSmall-cell carcinoma with an additional component of any of the histological types of NSCLC
  • WHO: World Health Organization; IASLC: International Association for the Study of Lung Cancer; SCLC: small cell lung cancer; NSCLC: non-small cell lung cancer.