This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Berg, O. Articles by Gordon, M. Search for Related Content PubMed PubMed Citation Articles by Berg, O. Articles by Gordon, M.

Progressive Growth Stages in the Development of Spontaneous Thyroid Tumors in Inbred Swordtails

Xiphophorus montezumae^*

( Aquarium, New York Zoological Society, New York, N.Y.)

The progressive stages in the development of the thyroid tumor of the swordtail, Xiphophorus montezumae, are as follows: 1. Day-old fish have 20–30 thyroid follicles, lined by flat or low cuboidal epithelium, scattered in the stroma around the ventral aorta, but not in the gills. 2. The follicle cells increase in size and become high columnar. 3. The number of thyroid follicles increases; the blood capillaries in the region of the follicles become and remain engorged with red blood cells. 4. The epithelial cells of the new follicles simultaneously increase in number and size; some of the blood capillaries rupture, and individual red blood cells are found close to the follicular cells. 5. The follicle configuration becomes distorted. 6. The follicles disintegrate. 7. Tumorous growths develop composed primarily of a mass of epithelial cells, microfollicles and hemorrhages. 8. Muscles in the region of the ventral aorta are surrounded by tumorous afollicular epithelial cells. 9. Tumor cells destroy the deeper musculature, the gill filaments, cartilage, and bone. (At this stage the thyroid tumor is visible externally.) 10. Death may be due to destruction of visceral gill arches and the consequential interference of normal respiration.

Highly inbred fish, from brother-to-sister matings between members of a thyroid tumor-susceptible strain, develop tumors earlier in life than those from less intensely inbred strains. This suggests that genes influencing the growth of thyroid cell elements accumulated in the members of the inbred strains.

A comparison was made between the thyroid follicles of wild young fish taken directly from their natural habitat in Mexico, and young fish laboratory-reared for seven generations. In both wild and laboratory fishes the number of follicles increase with age and length, but the increase is far more rapid in the laboratory fishes.

^* From the Genetics Laboratory of the New York Zoological Society at the American Museum of Natural History, New York 24, N.Y. Aided by a grant from the National Cancer Institute, National Institutes of Health of the U.S. Public Health Service (Myron Gordon, Principal Investigator).

Received 7/25/52.

This article has been cited by other articles:

				E. J. W. Geven, N.-K. Nguyen, M. van den Boogaart, F. A. T. Spanings, G. Flik, and P. H. M. Klaren Comparative thyroidology: thyroid gland location and iodothyronine dynamics in Mozambique tilapia (Oreochromis mossambicus Peters) and common carp (Cyprinus carpio L.) J. Exp. Biol., November 15, 2007; 210(22): 4005 - 4015. [Abstract] [Full Text] [PDF]

				J. W. Fournie, M. J. Wolfe, J. C. Wolf, L. A. Courtney, R. D. Johnson, and W. E. Hawkins Diagnostic Criteria for Proliferative Thyroid Lesions in Bony Fishes Toxicol Pathol, August 1, 2005; 33(5): 540 - 551. [Abstract] [Full Text] [PDF]