6i8 



Cancer Research 



toneum. Beneath the mesothelial cells of the peritoneum 

 there was coosiderdtle proliferation of branched ery- 

 throphores. The protoplasmic prolongations were uni- 

 f<Mrmly stippled by granules of red pigment. 



Thomas, 1931 b: An orange-red tumor infiltrated 

 the porterior porticm of the anal fin of a trout; the 

 branching erythrophores were embedded in a dense con- 

 nective tissue stroma. A small tumor, identical with 

 that on the fin, found on the surface of the peritoneum, 

 was interpreted by the author as a metastasis. 



SiUTH, CoATES and Strong, 1936: In a hybrid of 

 X. keUerU and P. mactdatus the authors found a tumor 

 arising from the red pigment cells. Brick red in color, 

 it grew in the region of the dorsal fin, invaded the skin 

 and adjacent tissues but none of the deeper structures. 

 Microscopically the pigmented tumor cells were large, 

 round or fusiform, and bore occasional dendrites. 



GUANOPHOROMA 



Only a single example of a neoplasm taking origin 

 from guanophores is on record. Takahashi (199) 

 described a tumor, 7 x 5 x 1.5 cm., on the left side 

 Dear the caudal fin of a "fat cod" Hexagrammos 

 atakii. On section the tissue was silver-white and 

 had a {peculiar sheen. Histologically, it was densely 

 infiltrated by short, yellow-white, needle shaped, 

 doubly refractile guanine crystals of great brilliance. 

 The crystals were present not only in the pleomor- 

 phic tumor cells but also in the interstitial tissues. 



XANTHOPHOROMA 



The only tumor purported to take its origin from 

 the xanthophores in the skin of a fish was reported 

 by Schroeders (179). An irregular orange-colored 

 tumor, the size of a bean, was located on the right 

 side of the trunk beneath and partly upon the dorsal 

 fin of a blenny. In the vicinity of this tumor were 

 se\'eral nodules the size of pin-heads. Histologically 

 the tumor consisted principally of large epithelioid 

 cells with vesicular nuclei and an oranj^e-yellow pig- 

 ment in the cytoplasm. .Single and multinucleated, 

 branched giant cells that also contained the pigment 

 were scattered through the tissue. The author be- 

 lieved that the cells were derived from the endo- 

 thelium of the lymphatic places and blood vessels. 

 The center of the mass was hemorrhagic and necro- 



tic. Whether it was a true neoplasm or a granulo- 

 matous reaction to injury must remain undecided. 



TUMORS OF NERVOUS TISSUES 



Only 7 pap)ers dealing with tumors of the nervous 

 system of 9 species of fishes were found in the 

 literature (Table 20). There is as yet no record of 

 a neoplasm of the brain or spinal cord: Takahashi 

 (199) and Haddow and Blake (68) each report a 

 ganglioneuroma arising in a spinal ganglion of a 

 flatfish. Thomas (203) observed a similar tumor in 

 a codfish and subsequently described a neuroepi- 

 thelioma of the olfactory plate in a gilthead (210). 



One of us (118) has studied the common nerve 

 sheath tumors of the snappers Lutianidae. A total 

 of 76 tumor bearing fishes were collected, which 

 were members of three species: the gray snapper 

 Lutianus griseus, the dog snapper L. jocu, and the 

 schoolmaster, L. apodus. The neoplasms generally 

 occurred along the course of the larger subcutaneous 

 nerves, particularly those of the head and dorsal 

 regions, as solitary or multiple relatively large firm 

 white masses (Fig. 36). Histologically, they closely 

 resembled the human neoplasms of the nerve sheath 

 group and were composed of two kinds of tissue: one 

 compact and richly fibrocellular (corresponding to 

 the Antoni A type); the other loose, reticulated, 

 and poorly cellular (Antoni B type). Palisade for- 

 mations of nuclei and fibrils were found in approxi- 

 mately one third of the tumors (Fig. 37). In some 

 regions the neoplasms were very cellular, the com- 

 ponent cells forming characteristic whorls (Fig. 38). 



Neurilemmomas of the autonomic nervous system 

 have been repwrted by Young and Olafson (236) in 

 25 brook trout Salvclinus jontinalis. The tumors 

 were tiny and not readily visible to the naked eye. 

 The pancreas and mesentery were most extensively 

 involved. The tumors were uniform and characteris- 

 tic in their structure. A peripheral band of collagen 

 surrounded concentric layers of fibrous tissue; at 

 the center of the growths there often was a group 

 of polyhedral cells with a variable amount of eosino- 

 philic and finely granular cytoplasm. No inclusion 

 bodies were seen, nor were bacteria found in the 



SpfciM 

 Codfidi Gadus tHcrhma 

 flatfish Liwtania yokokamae 

 Gflt bead Spoems amolut 

 Flatfiah Upiicrkombus megastom» 

 Goldfilh Carassius auralus 

 S aapp w Lmiiamus griseus \ 



Lutianus apodus >(76) 

 l.uiianus jocu j 

 Brook trout Sultdimus fontinalis (25) 



Table 20: Tomoi* or Nuvoos Ttsaou 



Site 

 Body wall 

 Spinal ganglion 

 Olfactory plate 

 Spinal ganglion 

 Subcutaneous 



Subcutaneous 



Pancreas ft mesentery 



Author 

 Tbonuu, 1927a 

 Takahashi, 1929 

 Thomas. 1932c 

 Haddow & Blake, 1935 

 Picchi, 1933 



Luck«, 1942 



Young ft Olafson, 1944 



