Masahito P, Ishikawa T, Sugano H, Uchida H, Yasuda T, Inaba T, Hirosaki Y, Kasuga A
J Natl Cancer Inst. 1986 Jul;77(1):291-8.
Liver tumors were observed in 2 South American lungfish (Lepidosiren paradoxa) and in 1 African lungfish (Protopterus amphibius) kept in 3 different aquariums in Japan for 2-5 years. In the first case a single, large nodule (70 X 60 X 55 mm) in the liver had been noted externally as a swelling 1 year prior to death. In the second case 2 rounded nodules (25 X 15 X 15 mm and 15 X 10 X 10 mm) were incidentally found at autopsy. In the third case, which also demonstrated abdominal swelling for 1 year preceding death, 2 green nodules (50 X 50 X 40 mm and 17 X 17 X 17 mm) were found in the liver together with multiple metastatic lesions. Histologically, variation was evident from tumor to tumor, even within the same animal. The most common histologic type was typical trabecular hepatomas. Admixtures of glandular or papillary structures were noted in some tumors. A region of poorly differentiated hepatocellular carcinoma with spindle-shaped cells in a sheetlike arrangement was noted in one case. The cause of these tumors is unknown. Since liver tumors were discovered at relatively high incidence (3/14 autopsied cases, including 6 species), lungfish seem to be predisposed to the development of liver tumors.
在日本3个不同水族箱中饲养了2至5年的2条南美肺鱼（南美星点肺鱼）和1条非洲肺鱼（原鳍鱼）体内观察到了肝脏肿瘤。在第一个病例中，肝脏上一个单个的大结节（70×60×55毫米）在鱼死亡前1年就已从外部被注意到是一个肿胀物。在第二个病例中，在尸检时偶然发现了2个圆形结节（25×15×15毫米和15×10×10毫米）。在第三个病例中，鱼在死亡前1年也出现了腹部肿胀，在肝脏中发现了2个绿色结节（50×50×40毫米和17×17×17毫米）以及多个转移灶。组织学上，肿瘤之间存在明显差异，即使在同一动物体内也是如此。最常见的组织学类型是典型的小梁状肝癌。在一些肿瘤中还注意到有腺管状或乳头状结构的混合。在一个病例中发现了一个低分化肝细胞癌区域，其中梭形细胞呈片状排列。这些肿瘤的病因尚不清楚。由于肝脏肿瘤的发现发生率相对较高（在14例尸检病例中有3例，包括6个物种），肺鱼似乎易患肝脏肿瘤。
