A Case of Small Rectal Carcinoid Tumor (7 mm in Diameter) with Liver Metastasis

Makoto lwasaki, Kentaro Yamagiwa, Kikuhiro Nakamura*, Takashi Noguchi**

Department of Surgery, Iwasaki Hospital
*Department of Surgery, Owase Municipal Hospital
**The First Department of Surgery, Mie University School of Medicine

A 70-year-old man was admitted to our hospital for the evaluation of liver masses. Ultrasonography revealed two hyperechoic masses at S₆ and S₇ of the liver. They appeared as low density areas on a CT scan, and celiac angiography revealed three tumor stains at S₆, S₇ and S₃, of the liver. The masses were diagnosed as metastatic liver tumors, and transcatheter arterial embolization was performed. While exploring for the primary site, we observed a flat tumor with a central depression in the rectum at the 6 o'clock location 8 cm from the anal ring, and local resection of the tumor was performed transanally. The tumor was small (7×6 mm) and its cut surface was yellowish-white. It was histologically diagnosed as a rectal carcinoid of type E (mixed type) in Soga's classification system. The vascular invasions were intensively positive, although, microscopically, carcinoid cells were confined to the submucosa. As there were no metastatic lesions other than liver metastases, partial hepatectomy was performed. Histologically, the masses were diagnosed as liver metastases of rectal carcinoid. The patient is currently healthy 27 months after surgery. It is very rare for a rectal carcinoid which is smaller than 1 cm in diameter and confined to the submucosa to metastasize to the liver. Therefore, in defining the stage of malignancy of rectal carcinoid, it is important to assess vascular invasion as well as tumor size and depth of invasion.

Key words
small rectal carcinoid, liver metastasis, vascular invasion

Reprint requests
Makoto lwasaki Department of Surgery, Iwasaki Hospital
333 Ishinden-cho, Tsu, 514-01 JAPAN

Accepted
January 8, 1992

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