t)60m 



Cancer Research 



mors were due to chronic irritation of the postopercular 

 skin by sand particles drawn into the mouth and ex- 

 pelled through the gill vent in the act of breathing. 



Thomas and Oxnes, 1930: A tumor was located 

 on the lower lip in each of 3 eels AnguiUa anguilla. 

 The lesions showed simple epithelial proliferation with 

 1 tendency to reduplication of the basal cell layer; 

 the basement membrane was preserved. 



Thomas, 1932: A 32 cm. brown trout Salmo tnttta 

 bore an irregular tumor at the level of the posterior 

 nuisin of the operculum. It measured 22x11x5 mm., 

 was not shar[dy demarcated, and in both gross and 

 microscopic structure was a typical papilloma. 



CoATCS, Cox and Smith, 1938: A tumor appeared 

 in the right mid-dorsal region of a six foot adult 

 electric eel Electrophorus electricus caught in the Ama- 

 xoo river basin and maintained in good health in a 

 fresh water tank at the N. Y. Aquarium for a period 

 of more than four years. The growth began as a small 

 elevation of the skin, pinkish-gray in color and a few 

 millimeters in diameter. Its maximum size of 2 x 2.5 

 cm. was reached in about ten weeks, when it was ex- 

 cised. No recurrence took place in the remaining year 

 and a half of life. The growth was a grape-like pedun- 

 culated mass composed of squamous epithelium com- 

 mingled with very many mucous celk. The epithelium 

 was supported by a central narrow fibrous core of 

 connective tissue. 



ADENOMA 



Adenomas have been repwrted in 11 species of 

 fish (Table 2). In 3 species the neoplasms involved 

 structures which have no exact counterp)art in man, 

 namely, the parabranchial bodies. These are two 

 small, often quite rudimentary organs, which He in 

 front of the true gills, and, like them, are hidden 

 from view by the opercula or gill covers. They are 

 composed of an extremely vascular tissue; the nu- 

 merous capillaries are surrounded by large cells 

 with dear or coarsely granular acidophilic cyto- 

 plasm. The function of the parabranchials is un- 

 knourn; some investigators consider them to be en- 

 docrine organs. 



Tumors of these structures have been observed in 

 codfish Gadus morhua from St. Pierre and Miquelon, 



and in 2 kinds of coalfish from the Pacific. In the 

 coalfish Pollachius brandti and Theragra chalco- 

 gramma in which the normal parabranchials vary in 

 weight from 0.1 to 0.4 gm., tumors of 9 and of 16 

 gm., respectively, have been described (199). The 

 tumor cells formed alveolar masses supported by a 

 scanty but richly vascular stroma. The cells re- 

 sembled those of the normal parabranchial bodies, 

 having a clear cytoplasm when they were adjacent 

 to the blood vessels, but with a granular cytoplasm 

 when more centrally located. The nuclei were large 

 and vesicular; mitoses were common. Necrosis of 

 the densely packed cells in the central part of the 

 alveolar mass led to the formation of pseudoacini. 

 Usually the tumors were not well delimited and infil- 

 trated the neighboring tissues. The investigators 

 who studied these growths at first hand fail to agree 

 as to their character. Takahashi (199) considered 

 them to be adenocarcinomas; Peyron and Thomas 

 (150) believed that they were benign or, at most, of 

 low-grade malignancy. 



Besides these tumors, adenomas have been re- 

 ported in various organs of 8 other species of fishes. 

 The tissue of origin was the liver in 3 species, and the 

 kidney, intestine, and ovary in the others. Most of 

 these tumors were solitary; some attained a very 

 large size, the tumor reported by Plehn in the liver 

 of a trout was twice the size of a man's fist. 



Biesele (13) studied the chromosomes in an ova- 

 rian tumor of a goldfish. Unfortunately no histologic 

 data are given and the author sp>eaks of the growth as 

 an "adenoma or adenocarcinoma." The average vol- 

 ume of the neoplastic chromosomes was twice that of 

 chromosomes in the cells of a healing skin wound 

 and in the nongerminal cells of a normal ovary. The 

 normal nuclei never possessed more than 4 nucleoli, 

 whereas 8 were found in the tumor cell nuclei. 

 Biesele concluded that the chromosomes of the gold- 

 fish tumor must be regarded as diplochromosomes. 



An adenoma of the catfish Ameiurus nebulosus, 

 which has not previously been described, occurred 

 in the right kidney of a female whose total length 



Tabu 2t AotMOMA 



8p«l« 

 Sand shark Prionae4 ^uctu 

 Trout So/rm tnOta 

 Ling MfflM «Mf«a 

 Codfidi GOmt morkua (2) 

 Coal Ftsh PdUckius brandti (2) 

 Coal Fish Tkeratra ckaUogramma 

 Purple Trout Saimc mykitt 

 Rainbow Trout Satwto gairdturii 

 PUty6sh Platypo9cUtu mactdatus (•everal) 

 G<Mfisb Carastiut anndtu 

 Catfish Amtiurui lu W a w w 



Site 

 Liver 

 Liver 

 Ovary 



Parabranchial body 

 Parabranchial body 

 Parabranchial body 

 Intestine 

 Liver 

 Kidney 

 Ovary 

 Kidney 



Author 

 Schrocders, 1908 

 Plehn, 1909 

 Johnstone, 1915 

 Peyron & Thomas, 1929 

 Takahashi, 1929 

 Takahashi. 1929 

 Thomas, 1931a 

 Haddow & BUke, 1933 

 Jahnel. 1939 

 Biesele. 1943 

 Luck€ ft Schlumberger 

 (not published) 



