Thymic and thymoma cytokeratin profiles

The thymus is a complex epithelial organ composed of various epithelial cell types.

Immunohistochemistry

Non-neoplastic thymus:

		CK7	CK8	CK10	CK13	CK14	CK18	CK19	CK20	Involucrin
	Subcapsular cells	8/91	1/91	0/91	0/91	9/91	0/91	9/91	0/91	0/91
	Cortex	2/91	0/91	0/91	0/91	0/91	1/91	8/91	0/91	0/91
	Medulla	7/91	5/91	0/91	3/91	9/91	6/91	9/91	0/91	0/91
	Hassall corpuscle	8/91	8/91	8/91	9/91	5/91	9/91	9/91	0/91	9/91
	Fisher exact test, p value (The null hypothesis is that the row categories are independent of the positivity or negativity for a cytokeratin. The p value is as defined by Anscombe.)	0.007	0.00008	0.0000006	0.0000004	0.0000003	0.000001	0.5	0.99	0.00000002

Thymomas (this paper by Kuo¹ is interesting, but the numbers of cases of each type are small. A previous paper by Savino is too old to provide a useful classification³.):

		CK7	CK8	CK10	CK13	CK14	CK18	CK19	CK20	Involucrin
	Spindle cell	5/51	5/51	1/51	0/51	4/51	5/51	5/51	0/51	0/51
	Small polygonal cell	2/61	1/61	0/61	1/61	6/61	1/61	6/61	0/61	0/61
	Mixed	4/51	3/51	0/51	0/51	5/51	3/51	5/51	0/51	0/51
	Organoid	5/51	5/51	5/51	4/51	5/51	5/51	5/51	0/51	5/51
	Large polygonal cell	5/61	2/61	1/61	0/61	2/61	1/61	6/61	0/61	0/61
	Squamoid	7/71	3/71	7/71	2/71	3/71	3/71	7/71	0/71	6/71
	Fisher exact test, p value (The null hypothesis is that the row categories are independent of the positivity or negativity for a cytokeratin. The p value is as defined by Anscombe.)	0.012	0.014	0.00008	0.008	0.009	0.004	0.999	0.999	0.00000036
	Overall	28/341	19/341	14/341	7/341	25/341	18/341	34/341	0/341	11/341

References

¹ Kuo, T. (2000). "Cytokeratin profiles of the thymus and thymomas: histogenetic correlations and proposal for a histological classification of thymomas." Histopathology 36(5): 403-14.

² Rosai J. World Health Organisation: Histological typing of tumours of the thymus. Berlin, Heidelberg:Springer-Verlag.

³ Savino, W. and M. Dardenne (1988). "Immunohistochemical studies on a human thymic epithelial cell subset defined by the anti-cytokeratin 18 monoclonal antibody." Cell Tissue Res 254(1): 225-31.

This page last revised 30.3.2004.

©SMUHT/PW Bishop