ScUumbtrger and Lucki — Tumors in Fishes 



659 



tinction can be drawn between these lesions and true 

 neopiasim, but dinkally the lesions of pox, unlike 

 true tumMS, usually regress and disappear entirely. 

 A detailed and well illustrated account of this di- 

 sease b given by Plehn ( 162). 



To the cases of papilloma reported in the litera- 

 ture we are able to add new examples from two other 

 qiedes. The first concerns 2 large tumors which 

 affected a common sucker Catostomus commersonnH 

 caught in a Wisconsin Lake. The fish was 8 years 

 old (as determined from examination of its scales), 

 its total length was 31 cm., the sex was uncertain. 

 The tumors were located on the right side; the larger 

 measured 6.1 x 5.5 x 4.0 cm. and involved almost 

 the entire lower half of the tail fin, the smaller tu- 

 mor, which measured 20 mm. in diameter, was lo- 

 cated 00 the tail, immediately in front of the caudal 

 fin (Fig. 1 ). Both ne<^lasms were firm, hemispheri- 

 cal masses which had the typical lobulated a^mpeai- 

 ance of pl^)illoma ( Fig. 2). Histologically, a delicate 

 arborescent stroma supported great masses of epithe- 

 lial cells (Fig. 3). Tall columnar cells formed the 

 layers adjacent to the connective tissue stroma; 

 toward the center of the epithelial masses the cells 

 become polyhedral and in places suggest "pearl" 

 formation (Fig. 4). The nuclei were conspicuous, 

 and usually contained one or two prominent nucleoli. 

 Among some of the epithelial masses were groups of 

 large davate cells (see footnote t); mucous cells 

 were not found. The tumors were sharply circum- 

 scribed, and nowhere extended into the subjacent 

 tiasue; there was no inflammatory reaction. 



Another kind of papillomatous growth occurred in 

 a small fish, the slippery dick Iri^Uo bivittata, which 

 inhabits tropical and semitropical waters (116). 

 Thirty tumor-bearing specimens were found among 

 apprcndmately 6,000 of these fish examined at the 

 Dry Tortugas, Florida. The tumors had the appear- 

 ance of flattened nodular elevations of the skin ; they 

 were grayish in color and soft in consistency, and 

 often th^ attained large size (Fig. 5), were most 

 usual on the lateral surfaces and commonly de- 

 stroyed the fins. Histologically, delicate fibrous pro- 

 jectlons of the corium were covered with many layen 

 of epithelial cells (Fig. 6). The growths frequently 

 eatMided into the corium, but infiltration of the 

 deq>er tissues was not observed. The cells of most 

 tuffion were much larger than the cells of the normal 

 epidenn; the cytoplasm was faintly granular; the 

 nuclei large and round or oval (Fig. 7). The nature 

 of this neoplastic distiM Is uncertain; whether these 

 growths are true nenpliwns or merdy eaglgemted 

 noD-neoplasUc epidermal proliferations b yet to be 

 determined. In some respects they seem to be related 



to the tumors of gudgeons dbcus sed above. Since 

 fish affected with these tumors can readily be kept 

 in indoor sea water aquaria, they dwidd prove ex- 

 cellent material for experimental inv e stiga tion. 



Abstracts of other reported cases of papfllewa 



ScHKOEoeas, 1908: In several species of gudfeoo 

 Gobio the author observed "fibro-epithdfc—sf s " In 

 some fish the tumors were aolitary, in othea BMiluplr. 

 In all instances they were sharply circumscribed, papil- 

 lomatom, and yellow-white in color. 



JoHNSTONX, 1912: An irregular caulifiowerlike 

 growth was observed on the snout of a halibat Bippo- 

 ^ssus hippogUu^ns, wfighfaig 120 pounds. On seedoa 

 there was marked prdiferation of the cornon, the over- 

 lying epithelium was intact with little evidence of hyper 

 plasia. 



JouNSTONK, 1925: About 1 docen whitish warts, 

 averaging 5 nun. in diameter, were scattered over the 

 unpigmented side of a pbdce PlewonecUs p t M tess a, The 

 growths were found to be impregnated with czystak of 

 iwgniHiiim^ phosphate. The corium was thickened and 

 showed evidbice of connective Usioe proliferation; the 

 overlying epithelium was thin. 



Johnstone, 1925: Flat cutaneous warts were 

 found on three plaice, JJmanda Im a n da caught in the 

 North Sea. One fish had a single tumor, 5 cm. in diam- 

 eter, near the eyt; another had multiple warts scattered 

 over the body, and the third had 2 growths, one supra- 

 orMtal and another on the dorsal fin. All of the tunors 

 were papillomas. 



Sacawa, 1925: In each of 2 goldfish Cwwsska 

 (uvatut there was a wart-like tumor the siae of a pea 

 on each of the pectoral fins. The hyperplastic epithelium 

 was arranged in papillary folds and in some areas 

 appeared kfnitinised, davate and mucous cells were 

 absent fai the tumor, though they were plentiful in the 

 normal skin. 



Takahashi, 1929: In a crucian carp Carauliu 

 C4trassius a tumor was located near the postcfior BBaifb 

 of the left operculum. It was a sharply drcumcribed 

 grayish-white growth, 3 x 2 x 0.5 cm. Histokfically, thns 

 was evidence of active epithelial proliferation with the 

 formation of epithelial "pearb" and numerous mitoaes. 

 The stroma was scanty, the suireuBdIng tissues were 

 not invaded, and metastases wen not found. After 16 

 months of observation the tumor appeared to be de- 

 creasfa«hi else. A biopsy wu taken and pieces trans- 

 planted to other fiih; none of the tranapkals grew; no 

 detaib were given. 



Thomas, 19J0: la 2 talcs Solm scim stmOsr tu- 

 mors weve found behhid and below the opercubr open- 

 ing on the pigmented side of each fish. Bich of the 

 tuoMCS saeesui ed about 3S x 20 x 7 nun.; they wees sss- 



sUe end grossly lobulsted; the oveilying lUn was devoid 

 of scabs. Ifssehre pegs of epithettum with tatact bess- 





ensndsd deep bto the 



itveskd that the adjeceni bone 

 was not bvolvcd. The author bftie\'ed that these tu- 



