. Author manuscript; available in PMC: 2016 Oct 1.

Published in final edited form as: J Thorac Oncol. 2015 Oct;10(10):1383–1395. doi: 10.1097/JTO.0000000000000654

Table 4.

Thymic neuroendocrine tumors covered by the 4^th edition of the WHO Classification of Tumours of the Lung, Pleura, Thymus and Heart.³ Conceptual changes are in bold (these tumors were counted among the combined thymic epithelial tumors in the 3^rd edition).

	Distinguishing histological criteria
Carcinoid tumors
Typical carcinoid	<2 mitoses/2mm²; no necrosis
Atypical carcinoid	<2 mitoses/2mm²; with necrosis; or 2–10 mitoses/2mm²; + or − necrosis
Large cell neuroendocrine carcinoma (LCNEC)	>10 mitoses/2mm²; no small cell features
Combined LCNEC	LCNEC combined with any thymoma(s) or thymic carcinoma(s)
Small cell carcinoma (SCC)	Typical SCC histology
Combined small cell carcinoma	SCC combined with any thymoma(s) or thymic carcinoma(s)