IMMUNOREACTIVITY OF SINUSOIDS IN HEPATOBLASTOMA - AN IMMUNOHISTOCHEMICAL STUDY USING LECTIN UEA-1 AND ANTIBODIES AGAINST ENDOTHELIUM-ASSOCIATED ANTIGENS, INCLUDING CD34

Sinusoids are found not only in the normal liver but also in certain l iver tumours, including hepatoblastoma, the most common malignant live r tumour in childhood, In this study, sinusoids in 12 hepatoblastomas, of various subtypes, and in normal liver were investigated with UEA-1 and antibodies against von Willebrand's factor, CD31 and CD34 to dete ct differences of possible diagnostic significance. In the normal live r, staining of sinusoids was seen with all these markers, but it was f ocal and confined to a few sinusoids near the portal tracts, in hepato blastoma, the endothelial markers reacted with the sinusoids to varyin g extents. UEA-1 and anti-CD34 usually stained the majority of these v essels, anti-CD34 staining greater numbers of sinusoids and with great er intensity. Immunostaining revealed that both number and spatial org anization of sinusoids in hepatoblastoma are dependent on the subtype, In addition to staining of endothelium, one of the two small cell hep atoblastomas exhibited strong immunoreactivity of the tumour cells for CD34. These findings show that the marked difference in sinusoidal im munoreactivity for CD34 between normal liver and hepatoblastoma could be useful for discriminating between non-neoplastic liver tissue and h ighly differentiated fetal hepatoblastoma. Our findings also show that small cell hepatoblastoma, in addition to acute leukaemia, should be considered when immunoreactivity for CD34 is found in small round and blue cell tumours in childhood.