Histopathologic correlation of hepatocellular carcinoma after transcatheter arterial chemoembolization with polyvinyl alcohol particle of various sizes.

Aim: Transcatheter arterial chemoembolization (TACE) is one of major treatment for unresectable hepatocellular carcinomas (HCC) and has been used as a neoadjuvant treatment before surgery. This study was to describe the histopathologic features of HCC after TACE with variously sized polyvinyl alcohol (PVA) particles.

Materials And Methods: Seventeen patients undergoing TACE with PVA followed by surgery for HCC were analyzed. The PVA particles used in TACE were categorized into two groups in respects of particle sizes: the group I, 47-90 μm (n=8) and the group II, >90-250 μm (n=9). The histopathologic features of the resected HCC were characterized with the emphasis on the number of thrombosed vessels and minimal diameter of arterioles/capillaries containing polyvinyl alcohol particles. The clinical results after TACE were also addressed.

Results: Histopathologic examinations showed that the median minimal diameters of arterioles containing PVA particles were 0.035 mm in group I and 0.06 mm in group II (p=0.0078). We observed the PVA particle in the sinusoidal spaces of non-tumourous liver in only one patient. However, no sinusoidal infarction was demonstrated in either group. Mean tumour necrosis rate was 67% vs. 61% for the group I and II, respectively.

Conclusions: The smaller PVA particles can reach and occlude more distal arteriolar capillaries, but rarely leak into non-tumourous hepatic sinusoidal spaces. Slightly better tumour necrosis rate after TACE can be achieved.