伊藤 嘉信, 赤松 興一, 宮内 聡一郎, 西信 正男, 大久保 啓二, 太田 康幸

Yoshinobu ITOH, Kouichi AKAMATSU, Souichirou MIYAUCHI, Masao NISHINOBU, Keiji OHKUBO, Yasuyuki OHTA

愛媛大学医学部第3内科

The Third Department of Internal Medicine, Ehime University School of Medicine

キーワード : Hypoechoic nodule, Small liver cancer, US guided fine needle biopsy

It is generally accepted that hyperechoic hepatocellular carcinoma (HCC) nodules contain more fat than non-nodular regions, but the cause of the hypoechogenicity of HCC is unknown. The aim of this study was to elucidate causes of hypoechogenicity by conducting a morphometrical examination. Nineteen patients with small liver cancer with hypoechoic nodules served as subjects. The echogenicity and the histological findings of the tumor nodules were compared. The reflection density of the photographs of the hypoechoic nodule in the nodules and in the non-nodular regions was measured with a reflection density meter (Konishiroku, PDA-60). The ratio of these two values was defined as an index of the hypoechoic level. Specimens of the liver nodules and non-nodular regions were obtained by ultrasonographically guided fine needle biopsy. The numerical density of the cells in the nodules and in the non-nodular regions was determined by the light microscopy of hematoxylin-eosin specimens and on the basis of the cellularity ratio. We traced the reticular fibers on photographs of silver-stained specimens of the liver-cell plates in the nodules and in the non-nodular regions by light microscopy. The length of the fibers was measured by applying the Textur Analyse System (Leitz). This ratio was defined as the circumference of the liver-cell plates ratio. The hyoechoic level index was not related to any increase in cellularity, but rather was related to the diminution of the liver-cell plates. The diminution of the liver-cell plates was in turn related to the grade malignancy of the HCC. It was thus assumed that the hypoechogenicity in small liver cancer was caused by a diminution of liver-cell plates.