Hepatic giant cell tumor is extremely rare, and only five cases have been reported of overt hepatocellular carcinoma, thus its histogenesis is controversial. Herein is reported a case of simultaneous hepatocellular carcinoma and osteoclast-like giant cell tumor in a single tumor. A liver tumor was found in a 74-year-old woman. Histologically the tumor consisted of two distinct components: mononuclear and multinuclear giant cells with osteoclastic giant cells, and a conventional hepatocellular carcinoma. The boundary between the two components showed transitional features. Immunohistochemistry showed that the osteoclast-like giant cells were CD68 and vimentin positive, but cytokeratin and AFP negative, while spindle-shaped cells were positive only for vimentin. In a portion of the hepatocellular carcinoma the cells were cytokeratin-8 and AFP positive. Ki-67 positivity was 10% for the hepatocellular carcinoma, 60% for the spindle-shaped cells, and 0% for the giant cells. It is possible that the tumor might have had a hepatocellular carcinoma origin, given the more highly proliferative sarcomatous changes and reactive osteoclast-like cells. This case provides a clue to the histogenesis of hepatic giant cell tumors.

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Reaction of 6-chloro-2-vinylidenecyclohexanone with sodium methoxide gave methyl 2-vinylidene-1-cyclopentanecarboxylate and methyl trans-2-(1-methoxyalkyl)-1-cyclopentanecarboxylate along with 6-methoxy-2-vinylidenecyclohexanone via a Michael addition-induced Favorskii rearrangement.

090ChemInform Abstract The reaction of 6-chloro-2-isopropylidenecyclohexanone (Ia) with NaOMe affords the product (IIa), which results by simple substitution, and the methyl 2-isopropylidene-1-cyclopentanecarboxylate (IIIa) as the main product along with the methyl trans-(1-methoxy-1-methylethyl)-1-cyclopentanecarboxylate (IVa). The products (IIIa) and (IVa) are formed by Favorskii rearrangements of the cyclohexane skeleton. These rearrangements are started by a Michael addition of NaOMe to the carbon-carbon double bond of (Ia). The analogous reactions of 2-ethylidene-(Ib) or 2-benzylidene-6-chlorocyclohexanone (Ic) with NaOMe afford the products (IVb) -erythro:threo = 20:18 -and (Vb) or (IVc) -erythro:threo = 33:29 -and (VIc), which are all formed by Michael addition-induced Favorskii rearrangements.