A thymic carcinoma identical to the lymphoepithelioma-like carcinoma of the upper respiratory tract. The role of EBV in the aetiology is not yet certain.
There is a bimodal age distribution, with a first peak in the second decade. Cases in children have been reported1.
There is no association with myasthenia gravis but hypertrophic osteoarthropathy has been reported in children.
The tumour is usually incompletely encapsulated.
The epithelial cells form a syncytial pattern. Nuclei are large with very prominent nucleoli. The lymphocytic component may be intimately admixed or form small clusters. It consists of a mix of lymphocytes and plasma cells. There may be an infiltrate of eosinophils and granulomas may occur.
Undifferentiated carcinoma positive for EBV, with a dense fibrous stroma but lacking a significant lymphoid component is provisionally included in this category.
|
Tumour cells |
|||
|
Cytokeratin |
2/22 |
||
|
positive0 |
|||
|
negative0 |
|||
|
negative0 |
|||
|
negative0 |
|||
|
2/22 |
|||
|
often positive0, 2/22 |
|||
|
focal or negative0, 2/22 |
|||
|
0/22 |
|||
|
0/22 |
|||
|
0/22 |
|||
|
Lymphocytes |
|||
|
negative0 |
|||
|
positive0 |
|||
|
positive0 |
|||
|
a minority B-cell component is positive0 |
|||
|
negative0 |
|||
|
negative0 |
|||
Half the cases show evidence of EBV infection, with a higher proportion in childhood and teenage cases.
Poorly differentiated squamous cell carcinoma with a lymphoplasmacytic infiltrate.
Seminoma
Embryonal carcinoma
The prognosis is poor with an average survival of 16 months, irrespective of the EBV status.
0 Tumours of the Lung, Pleura, Thymus and Heart. WHO Classification of Tumours. IARC Press 2004.
1 J Rosai et al. Histological typing of tumours of the thymus. WHO International histological classification of tumours. Springer-Verlag, second edition, 1999.
This page last revised 6.1.2006.
©SMUHT/PW Bishop