Thymic hepatoid carcinoma

Definition

There has been a case report of a thymic carcinoma showing hepatoid differentiation.

Clinical features

The patient was a 70 year old woman. No other primary tumour site became apparent during two years follow up.

Histopathology

The tumour was not encapsulated. It consisted of sheets of cells with a vague nodularity. The tumour cells resembled hepatocytes. There were frequent intracytoplasmic hyaline globules, which were diastase-resistant. There were no intratumoral immature T-cells. There was no lobularity, no epidermoid differentiation or keratinisation and no perivascular spaces. No conventional thymoma or germ cell tumour was seen.

Immunohistochemistry

	CK7	positive
	CK19	positive
	CK5/6	negative
	CK8/18	negative
	CK20	negative
	EMA	strongly positive
	CEA	positive
	a-1-antitrypsin	globules positive
	a-1-antichymotrypsin	cytoplasm diffusely positive
	HepPar-1	faintly positive
	AFP	negative
	bHCG	negative
	PLAP	negative
	LCA	negative
	CD15	negative
	CD30	negative
	CD34	negative
	CD56	negative
	CD57	negative
	CD68	negative
	CD99	negative
	S-100	negative
	HMB45	negative
	MART-1	negative
	Vimentin	negative
	Actin	negative
	Desmin	negative
	Calretinin	negative
	Chromogranin	negative
	Synaptophysin	negative
	ER	negative
	PR	negative

Differential diagnosis

Hepatoid yolk sac tumour of the thymus
Metastatic hepatocellular carcinoma

References

Franke, A., P. Strobel, et al. (2004). "Hepatoid thymic carcinoma: report of a case." Am J Surg Pathol 28(2): 250-6.

This page last revised 29.3.2004.