662 



Cancer Research 



a cylindrical mass, measuring 3 x 1.2 cm., arose in 

 the skin near the cc^ulatory appendages of a cat 

 shark Scyilium catulus. It was very firm, and had a 

 small, very vascular cavity at its dbtal end. Histo- 

 logically, a thick layer of cutaneous epithelium cov- 

 ered a more or less homogeneous mass, which the 

 author believed represented enamel or dentin. The 

 cavity noted grossly was occupied by greatly dilated 

 blood spaces that appeared angiomatous. 



Corresponding more closely to odontomas of man 

 are the lesions described by Plehn (160) in the jaws 

 of two fresh-water trout. In both cases the tumors 

 consisted of large congeries of atypically formed 

 teeth. Innumerable, more or less confluent, nodular 

 tumors, had developed from all the tooth-bearing 

 surfaces, vix., both dental plates, the hyoid bones 

 and, in one case, the vomer. As the author showed 

 in a pbot(^r2q>h, the tumors had attained such a 

 large size that the fishes could not close their mouths, 

 thus making feeding impossible. 



Another example of an odontoma was reported by 

 Roffo (172) in a marine fish, the croaker Micropo- 

 gon opercularis. The tumor formed a firm, pale mass 

 on the upper dental plate. Histologically it con- 

 sisted of tooth germs irregularly scattered through a 

 connective tissue stroma. The paper is accompanied 

 by a number of excellent figures which show gross 

 appearance, roentgenograms, and histologic struc- 

 ture of the ne(^lasm. 



Only one case of adamantinoma has been recorded, 

 by Thomas (202). The tumor formed a mass, 2.5 

 X 1 cm., that had infiltrated the maxilla and pro- 

 truded into the oral cavity of a haddock Melano- 

 grammus aegtifinus. Histologically it corresponded 

 in all details to the cystic adamantinomas of man. 



EPITHELIOMA (EPIDERMOID CARCINOMA) 



Some of the neoplasms reported in the literature 

 as epithelioma are only questionably malignant. In 

 this review we have placed certain tumors which 



wore re|X)rted as epitheliomas under the heading of 

 p>apilloma because of their structure and absence of 

 invasion. There remain a considerable number of 

 tumors of pavement epithelium that are invasive or 

 exhibit other evidence of malignancy, which prop- 

 erly may be regarded as epidermoid carcinomas. 

 They have been observed in 12 different species of 

 fishes (Table 4). The tissues of origin were the skin, 

 the lips or oral mucosa, and, in a single case, the 

 urinary bladder. In general, these tumors had the 

 structure of mammalian epidermoid carcinomas; in 

 some cases, as in that of Bashford, Murray and 

 Cramer (6) the resemblance to squamous cell car- 

 cinomas in mammals was reported as striking. It 

 must be remembered, however, that the epithelial 

 covering of fishes does not keratinize, hence the 

 typical cornified "pearls" of mammalian epitheli- 

 omas are not formed, although nonkeratinized col- 

 lections of concentrically arranged celb are frequent- 

 ly seen. 



Several of the tumors under discussion resembled 

 papillomas, in their general appearance, but differed 

 in that they sent long, usually ill-defined pegs of 

 solidly packed cells into the corium or deef>er tissues. 

 Thus, in the case reported by Murray (141) the 

 tumor invaded the underlying skeletal muscle. None 

 had metastasized at the time of examination. 



The lips and oral mucosa are the most common 

 sites of epitheliomas in fishes; neoplasms have been 

 observed in these locations in 7 species. The first 

 record of an epithelioma in a fish reported by Mc- 

 Farland (136), deals with such a tumor. A lobu- 

 lated, papillary growth, 4 cm. in diameter, involved 

 the lower lip and adjacent mucosa of a catfish 

 Ictalurus catus; multiple small nodules were present 

 on the upper lip and the neighboring skin. Histo- 

 logically the neoplasm consisted of a fungoid mass 

 which was composed of epithelial cells supported by 

 a delicate vascular stroma. The larger tumor was 

 definitely invasive. The tumor reported by Clunet 



Catfish liUdanu eatus 

 Carp CypHmui ecrpio (2) 

 Carp Cyprinus carpio 

 Stickleback Spinwhia spituukia 

 Tench. Tinea tinea (2) 

 Carp Cyprinus carpio 

 Gotdfiih Carassius auraius 

 Barbel Barbus tutgaris 

 "LcNes" Ckomdrostema soeUa 

 Croaker Poionias ckramis (2) 

 Whiting Mertangus mtrtangms 

 Codfiah PaUacMns firens 

 Biajaca CickUsowf Utracantkus 

 Catfiab Amdmnu mtbtdtt (166) 



Tabls 4: ErmiKUOMA (Epidbimoid CAiaiioHA) 



Siu 

 Both lips 

 Skin of head 

 Not given 

 Skin of trunk 

 Lips 



Fins ft operculum 

 Bladder 

 Lower Up 

 Oral mucosa 

 Lips 



Mandible 

 Lower Hp 

 Skin about orbit 

 Lips, oral mucosa 



Author 

 McFarland. 1901 

 Dauwe ft Pennemann, 1904 

 Bashford, Murray & Cramer, 1905 

 Murray, 1908 

 Fiebiger, 1909a 

 Fiebigcr, 1909a 

 Plehn, 1909 

 Qunet, 1910' 

 MaxsarelU, 1910 

 BeatU, 1916 

 Johnstone, 1924 

 Williams, 1929 

 Pucnle-Duany, 1930 

 Luckt ft Schlumberger, 1941 



