CASE REPORT 
Annals of Nuclear Medicme Vol. 3 No. 2, 99-l02, 1989 
Hepatic carcinosarcoma demonstrated by Ga-67 scintigraphy 
Seishi JlNNOUCHI,* Hiroaki Hosrn,* Katsushi WATANABE,* Riruke MARUYAMA** and Tadashi KOUNO** 
*Department of Radiology and **Second Department of Pathology, Miyazaki Medical College Hospital 
A case of a primary hepatic carcinosarcoma, a very uncommon liver tumor in adults, demonstrated by Ga-67 scintigraphy, was reported. The liver image showed a lesion of low activity in the left lobe of the liver, whereas the Ga-67 image showed a moderate accumulation in the lesion detected by the liver scan and further indicated a high accumulation extending downwards from the hepatic lesion. An autopsy revealed that the huge abdominal tumor was composed of hepatocellular carcinoma and malignant mesenchymoma in the left hepatic lobe and in the lower part of the tumor, respectively. The Ga-67 image dernonstrated these two different histological components of the tumor. 
Key words : Ga-67, liver tumor, carcinosarcoma. 
INTRODUCTION 
PRIMARY CARClNOSARCOMA of the liver is extremely rare, and to our knowledge, there have only been seven cases reported as primary carcinosarcoma.1-7 Radiological findings of this tumor had no specific features; therefore, it is very difficult to accurately diagnose a liver tumor as primary carcinosarcoma. We report here a case of so-called primary carcinosarcoma which was suspected to consist of two different components based on the characteristic finding in Ga-67 scintigraphy. 
CASE REPORT 
A 55-year-old man was referred to Miyazaki Medical College Hospital complaining of upper abdominal fullness. His previous medical history was not remarkable, except for a duodenal ulcer which had been treated conservatively for the past 20 years. 
On admission a snowman shaped mass of 10 and 12 cm in diameter originated from the liver was palpable in the upper abdomen. The upper part of 
Received December 25, 1987; revision accepted December 23, 1988. 
For reprints contact : Seishi Jinnouchi, M.D., Department of Radiology, Miyazaki Medical College Hospital, 5200 Kihara, Kiyotake-cho, Miyazaki-gun, Miyazaki 889-16, JAPAN 
the tumor was hard and the lower part was slightly soft, and it moved during respiration. Liver function tests, serum AFP and serum CEA levels were all within normal values. Upper GI series revealed that the lesser curvature of the stomach was compressed by this huge tumor and that there was no mucosal irregularity. Abdominal CT (Fig. 1) showed a huge liver tumor which grew and extended downward from the left hepatic lobe. Abdominal angiography suggested the presence of a malignant liver tumor showing a hypervascular pattern which was supplied by the left hepatic artery. Liver scintigraphy and Ga-67 scintigraphy were performed with a gammacamera (400T, G.E.) using 185 MBq of Tc-99m phytate and 111 MBq of Ga-67 citrate, respectively. The liver image showed a lesion of low radioactivity in the left lobe (Fig. 2). The Ga-67 image showed a moderate accumulation in the lesion seen in Fig. 2 and further indicated a high accumulation extending downwards from the hepatic lesion (Fig. 3a, b). The patient died one month later from upper GI bleeding. 
An autopsy showed that the right hepatic lobe was occupied by cirrhosis and that an encapsulated snowman shape mass originated in the left hepatic lobe and grew downward roundly. Macroscopically, the upper half of the mass (originating in the liver) was composed of a solid tumor, whereas the lower half was of another tumor with signs of hemorrhage and necrosis (Fig. 4a, b). Microscopically, the upper portion consisted of a hepatocellular carcinoma showing a trabecular form (Fig. 5a), while the lower portion was occupied by a malignant mesenchymoma which comprised proliferations of spindle cells accompanied with atypical polynuclear giant cells, rhabdomyocells, leiomyocells, and osteoid formation (Fig. 5b). Sections from the midportion of the tumor revealed that these two different histological components mentioned above coexisted (Fig. 5c). This malignant tumor was thought to be a collision tumor, one type of so-called carcinosarcoma. 
DISCUSSION 
Primary hepatic sarcoma is an uncommon liver tumor, and carcinosarcoma or malignant hepatic mixed tumor is very rare. Mayer and Fould classified carcinosarcoma into three groups according to the possible methods of their origin ; l) combination tumors, 2) composition tumors, and 3) collision tumors.8,9 On the other hand, Edmondson4 divided them into two groups as summarized in table 1. 
The present case was thought to be a collision tumor or a combined carcinoma and sarcoma in Meyer's or in Edmondson's classification based on its histological distribution. Seven cases previously reported as carcinoma and sarcoma are shown in table 2 together with the present case. Eight cases were all elderly or middle-aged males with liver cirrhosis. The serum AFP levels were examined in three cases, but were all negative. Concerning Ga-67 scintigraphic findings, no results were reported in seven of the cases. In the present case, the Ga-67 image showed a moderate accumulation in the upper part of the tumor and a high accumulation extending to the lower part. The tumor was suspected therefore to consist of two different histological components. Comparing the findings in the Ga-67 image with the histological distribution of the tumor, the moderate accumulation reflected hepatocellular carcinoma and the high indicated sarcoma, which occupied the lower part of the tumor and showed hemorrhage and necrosis. Although the mechanism of accumulation, as shown in the Ga-67 image of the neoplasm, is not clear, the differences between the accumulation rates may partially reflect its histological character. It seems that Ga-67 scintigraphy is a useful diagnostic tool for the detection of combined carcinoma and sarcoma of the liver. 
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