ScMumberger and LucH — Tumors in Pishes 



665 



soft, pale gray, and invaded the body wall. The 

 component cells were cuboidal and had large spheri- 

 cal nuclei; the stroma was abundant. Takahashi 

 (199) regarded it as an adenocarcinoma of unknown 

 origin. 



The ovarian tumor in a pike Esox lucius reported 

 by Haddow and Blake (68) was a soft mass, 7x3 

 cm., near the anterior pole of the left ovary; several 

 smaller nodules accompanied the main tumor. 

 Microscopically, the structure was that of an adeno- 

 carcinoma, apparently derived from germinal epi- 

 thelium. 



The cancer of the digitiform or rectal gland in 

 the coalfish Theragra chalcogramma reported by 

 Takahashi (199) is of interest because of its exten- 

 sive metastases and its origin in a structure having 

 no homologue in man or the higher vertebrates. This 

 gland is a short tubular body, the duct of which 

 opens into the lower end of the intestine; its func- 

 tion is unknown. The mass was firm, coarsely nodu- 

 lar, grayish white, and as large as the head of a 

 child. Histologically it was an adenocarcinoma that 

 contained cystic spaces partly filled by papillary pro- 

 jections. Metastases and secondary tumors due to 

 direct extension were present in the liver, stomach, 

 intestine, spleen, urinary and swim bladders. 



Abstracts of other reported cases of Adenocarcinoma 



Schmey; 1911: A retroperitoneal mass 7 z 3.S cm. 

 was found in an eel AnguUIa anguUla approximately 3 

 years old. The tumor could be readily freed from the 

 abdominal musculature, but could not be separated 

 from the left kidney. Microscopically it consisted of 

 irregulariy arranged tubules and cysts which passed 

 over into normal renal substance without sharp demarca- 

 tion. 



Plehn, 1924: The abdomen of an eel AnguiUa 

 angittUa, 53 cm. in length, was greatly distended by a 

 tumor 7 X 3.5 cm. The lesion was apparently malignant, 

 having destroyed the posterior half of the kidney and 

 invaded the anterior portion, but no metastases were 

 found. No histologic description accompanied the re- 

 port 



Takahashi, 1929: At the left angle of the mouth 

 of a coalhsh Theragra chalcogramma was a tumor that 

 had extended into the skin of the operculum on the 

 same side. The neoplastic epithelial cells were grouped 

 to form alveoli and invaded the adjacent structures. 

 The tissue of origin was not identified. 



Laouvt, 1935: The palate of a moray Muraena 

 hdena was the site of a large tumor which had its origin 

 in the glands Kattered throughout the mucosa. The 

 malignancy of the tumor was manifested by partial 

 absence of a basement membrane, atypical structure of 

 the cells, and extensive local invasion. Metastases were 

 not found. It is well known that the bite of Morays \% 

 poisoDOUt, due to the secretion of venom by the mucous 



glands in the palate. TesU showed that the venom of 

 the cancerous glands was less active than that of the 

 normal ones, but the effecU it produ uJ bypcicm ia 

 and cellular degcneritioo — were quafitativdy the same. 



THYROID TUMORS- 



No tumor or tumor-like lesloo of fifdws has re* 

 ceived more attention than that of the thyroid 

 gland. Such "tumors" are most frequently observed 

 in trout reared in hatcheries and less often in other 

 species living In ponds or aquaria (98, 131, 178, 190, 

 194) (Table 6). Attention was first called to thb 

 condition by Bonnet (14) who described an epi- 

 demic that destroyed over 3, (XX) lake trout Salmo 

 lacustris in a fish hatchery between February and 

 June of 1883. All had tumors at the ventral junc- 

 tion of the gills. 



Scott (182), who observed enlargement of the 

 thyroid of brook trout Salvelinus jontinaUs reared 

 in a single fwnd, was the first to identify it as "car- 

 cinoma" ( 1891 ). The lesion began as a local hypere- 

 mia of the oral mucosa followed by nodular rou^- 

 ening in the midline of the ventral wall of the 

 pharynx just behind the tongue. The nodules in- 

 creased in size, and ultimately filled the oral cavity, 

 protruding beyond the opercula. On section the 

 masses were found to be composed of distended ir- 

 regular acini lined by cuboidal or columnar cells. 

 Some of the alveoli were filled with colloid; the 

 lumen of others was small and the cells arranged 

 in papillary folds. Islands and acini of thyroid 

 cells were found scattered throughout the adjacent 

 tissues. 



The view that these tumors are true cancers has 

 been maintained by numerous investigators (25, 58, 

 78, 153, 156, 195). In 1914 Gaylord and Marsh 

 published their monc^^ph entitled "Carcinoma of 

 the Thyroid in the Salmonoid Fishes" (53), based 

 on tumors observed in several thousand trout at 

 VS. government fish hatcheries. A study of the his- 

 tologic descriptions and many excellent photomicro- 

 graphs reveals, however, that the large majority of 

 the tumors are examples of h)'perplasia and coUoid 

 storage, without evidence of malignant change. 

 Nevertheless, it cannot be denied that amoQg the 

 thousands of goiters there probably were insUnoet 

 of adenocarcinoma. Gaylord and Marsh theimdvfs 

 reported two cases in which metastases were found. 

 In one, the metastatic nodule was present In the wall 

 of the rectum, where it was covered by intact rectal 

 mucosa. In the other the metastasis was on the tip 

 of the lower jaw and may merdy represent aberrant 

 thyroid tissue. Thb b made more likely in view of 

 the studies of Gudernatsch (66) who pointed out 



