Primary liver sarcomatous carcinoma: report of two cases and review of the literature.

Primary liver sarcomatous carcinomas (PLSCs) are very aggressive tumors. They are characterized by a fast clinical course, and therefore need a prompt histological diagnosis. Here, we report two cases of PLSC. One arises in a non-cirrhotic liver and the other in cirrhosis, with differences in onset and histological features. Special emphasis is put on the expression of albumin and HCC markers, and their possible usefulness in the diagnosis. The English literature of the last 20 years was revised (92 cases). Immunohistochemistry was performed manually or automatically; in situ hybridization (ISH) technique for albumin mRNA detection was carried out. The sarcomatoid components in both cases were immunoreactive for K8/18, Glutamine Synthetase and EZH2, and negative for Glypican 3, SMA, caldesmon, desmin, DOG-1, CD34, CD31, CD117, CD56, and alpha-fetoprotein. The detection of albumin mRNA by ISH was negative in the sarcomatoid component in both cases. PLSC represents a diagnostic challenge for pathologists, especially in its "pure" form: neither albumin mRNA detection nor HCC markers are useful for the diagnosis: positivity for K8/18 and the negativity for the mesenchymal markers seem to represent the main tools for the histological diagnosis.