Schlumberger and Lucke — Tumors m Fishes 



661 



was 35 cm. The growth measured 8x8x6 mm., was 

 pale gray, and sharply delimited, though not encap- 

 sulated; its cut surfaces were moist but not bloody. 

 It was composed of acini that were irregular in size 

 and shape, and often greatly dilated. The lining 

 epithelial cells varied from low cuboidal to tall col- 

 umnar elements; their nuclei were large, vesicular, 

 and had prominent nucleoli ; mitotic figures were un- 

 common. Papillary projections extended into some 

 of the cystic spaces; the scanty stroma was poorly 

 vascularized. This tumor was found in a fish which 

 also had massive epitheliomas of the lip and mouth. 



Abstracts of other reported cases of adenoma 



ScHROEOERS, 1908: Multiple adenomas were 

 found in the liver of a shark Prionace gUmcus caught in 

 the Black Sea. The surface of the liver was covered 

 with whitish, spherical nodules ranging in size from a 

 pin-head to a walnut. Similar nodules were found 

 scattered throughout the substance of the liver. On 

 section the nodules were firm and pale yellow. His- 

 tologically, the neoplastic cells resembled normal liver 

 celh except that they were smaller and contained less 

 fat. The transition from normal cells to tumor cells 

 was gradual. 



Johnstone, 1915: One ovary of a ling Molva 

 moiva was occupied by a mass consisting of cystic 

 spaces with walls of varying thickness. On section, p 

 clear, glair>' fluid was found in the cysts. Some areas 

 of fibrosis were also present in this lesion which may be 

 classified as a papillary cystadcnoma of the ovary. 



Plehn, 1924: The liver of a lake trout Salmo trutta 

 was the site of a mass of cysts filled with clear fluid or 

 gelatinous material. The largest of the cysts measured 

 15 cm. in diameter; the entire tumor was twice a5 

 large as a man's fist. Between the cysts were remnants 

 of normal liver, strands of connective tissue, and iso- 

 lated bile ducts. The growth was regarded by Plehn a 

 a cystadenoma of the liver. 



Peyron and Thomas, 1929: The authors observed 

 tumors of the parabranchial bodies in two codfish 

 Gadtu morhua. In one. a large tumor, 4 x 3 x 1.5 

 cm., occurred on the right side, elevated the operculum. 

 and protruded beyond its posterior margin; the gills 

 were compressed. In the other case the tumors were 

 bilateral and the size of a cherry. The histologic ap- 

 pearance has been discussed above. 



Takahashi, 1929: In two specimens of co.ilfish 

 PoUacfiius brandti each parabranchial body was the seat 

 of a tumor. In both, the growths on the riffht were the 

 size of a small heh's egg, those on the left were twice 

 as large. In another variety of coalfish Theragra ckal- 



cogramma a large tumor was present in the left para- 

 branchial body. This tumor was soft in consistency, 

 pooriy circumscribed, and contained many cystic and 

 necrotic areas. The surface was ukented. The his- 

 tologic structure was as already described. 



Thomas, 1931 a: In a purple trout Salmo mykiu, 

 25 cm. in total length, the author found a broadly ses- 

 sile, hemispheric tumor in the intestine midway between 

 stomach and anus. It measured 20 x 18 x 8 mm., was 

 gray-white and moderately firm; there was no ulcera- 

 tion of the surface. Histologically, the entire thickness 

 of the intestinal wall was infiltrated by the cystic neo- 

 plasm. The lining epithelium of the cysts was strati- 

 fied, the cells basophilic with occasional abcKmnal mi- 

 toses. Blood vessels were not numerous; coUectioos of 

 lymphocytes were abundant. 



Haooow and Blake, 1933: The authors described 

 a hepatoma found near the anterior margin of the liver 

 of a 4 to 5 year old rainbow trout Salmo gmrdnem. 

 It was spherical, about 1.5 cm. in diameter, and paler 

 and more firm than the surrounding hepatic tissue. No 

 metastases were present. Microsco|Hcally the tumor 

 was composed of actively proliferating potyhedral ceUs, 

 only slightly different from the parent liver cells. The 

 arrangement of the cells resembled that of normal liver, 

 except for the presence in the tumor of an abundant 

 fibrous stroma. Although the adenoma was not en- 

 capsulated, it had not infiltrated adjacent structures. 



Jahnel, 1939: This author notes the frequent oc- 

 currence of cystic adenomas of the kidney in the tropical 

 aquarium fish Platypoedlus maadatus. No further de- 

 tails are given. 



DENTAL TUMORS 



Teeth are cutaneous appendages; in manunals 

 they may be regarded as modified papillae of the oral 

 mucosa. In elasmobranch fishes, such as sharks and 

 rays, the small placoid scales, which give the rough 

 granular feel to the skin of these animals, represent 

 phylogenetically the most primitive teeth of verte- 

 brates. Each scale has a pointed tooth-like shape; 

 its base is embedded in the dermis, its apex pro- 

 trudes above the surface. A central vascular con- 

 nective ti.«isue pulp is surrounded by a layer of odon- 

 toblasts which form the hard dentin. The free sur- 

 face is coated by enamel, a product of modified 

 epithelial cells. 



In Table 3 Is given a summary of dental tumors 

 which have been observed in 4 species of fishes. 



A neoplasm of "cutaneous teeth" was reported as 

 a "dermal odontoma" by Ladreyt (108). The tumor, 



Spadtt 

 Trout — tpedct not ffiven (2) 

 Croaker Micropcgon optretdaris 

 Haddock iitlanogrammus atglifinus 

 Cat shark SeyUium eatulus 



TaMS J: DCWTAL TOMOM 



Site 



Dental plates k hyoid bon« 

 Upper dental pUte 

 BfaxiUa 

 SUa 



Avtkor 

 Plehn. 1912 

 Roflo. 1925 

 Tbonuu, 1926 

 Udreyt, 1929 



