14
LEROY C. STEVENS
are derived from germ cells, as is most likely, it means that both the
primordial germ cells (as shown in strain 129 mice) and probably
spermatogonia are susceptible to teratocarcinogenesis in mice. It will be
mentioned later that we have repeated Bresler's experiment (1959,
1964) using strain 129 mice, and failed to obtain teratomas.
VIII. Extragonadal Teratomas
Abell et al. (1965) believe that germ cell neoplasms whether they be
in the testis, ovary, mediastinum, retroperitoneum, or region of the pineal
gland possess the same histopathological patterns of growth, and Friedman (1959) concluded that the testis must be excluded as the primary
site before a diagnosis of primary extragenital choriocarcinoma can be
made. When it was possible to examine the entire testis, he always found
a tumor or a cicatrix in patients with retroperitoneal choriocarcinoma or
embryonal carcinoma.
Schlumberger (1946) postulated that mediastinal teratomas originated
from the third pharyngeal pouch, which is the anläge of the thymus.
According to Friedman (1959), on the other hand, the fact that embryonal, teratoid, and trophoblastic growths of the mediastinum are often
found in association with germ cell tumors makes it difficult to accept
Schlumberger's concept that these tumors are of somatic rather than of
germinal origin.
Coccygeal and pharyngocranial teratomas are congenital growths
considered by most authors to be remnants of "parasitic twins," and not
of germ cell origin.
There is little evidence permitting a good explanation of the origin
of extragonadal teratomas. The opinion of Friedman (1959) and Dixon
and Moore (1952) that nongonadal teratomas are derived from ectopic
primordial germ cells is plausible. It has been shown for man and the
mouse (Mintz, 1960) that some migrating primordial germ cells fail to
reach the gonad, and that they may become lodged in extragonadal
sites. They may constitute potential foci of teratomas.
The author (1964) transplanted the genital ridges from 12.5-day fetal
strain 129 mice to the spleens of adults, and some of them developed into
testes with teratomas. This means that teratomas will develop in abnormally located germ cells, and weakly supports the theory that extragonadal teratomas are derived from displaced germ cells. The fact that
two-celled mouse ova will develop into teratoid growths when transplanted to the adult testis (Stevens, unpublished) also weakly supports
this theory.
IX. Pathogenesis
According to Willis (1962a), nearly all teratomas including those of
the testis are congenital or originate in infancy or childhood. On the
LEROY C. STEVENS
are derived from germ cells, as is most likely, it means that both the
primordial germ cells (as shown in strain 129 mice) and probably
spermatogonia are susceptible to teratocarcinogenesis in mice. It will be
mentioned later that we have repeated Bresler's experiment (1959,
1964) using strain 129 mice, and failed to obtain teratomas.
VIII. Extragonadal Teratomas
Abell et al. (1965) believe that germ cell neoplasms whether they be
in the testis, ovary, mediastinum, retroperitoneum, or region of the pineal
gland possess the same histopathological patterns of growth, and Friedman (1959) concluded that the testis must be excluded as the primary
site before a diagnosis of primary extragenital choriocarcinoma can be
made. When it was possible to examine the entire testis, he always found
a tumor or a cicatrix in patients with retroperitoneal choriocarcinoma or
embryonal carcinoma.
Schlumberger (1946) postulated that mediastinal teratomas originated
from the third pharyngeal pouch, which is the anläge of the thymus.
According to Friedman (1959), on the other hand, the fact that embryonal, teratoid, and trophoblastic growths of the mediastinum are often
found in association with germ cell tumors makes it difficult to accept
Schlumberger's concept that these tumors are of somatic rather than of
germinal origin.
Coccygeal and pharyngocranial teratomas are congenital growths
considered by most authors to be remnants of "parasitic twins," and not
of germ cell origin.
There is little evidence permitting a good explanation of the origin
of extragonadal teratomas. The opinion of Friedman (1959) and Dixon
and Moore (1952) that nongonadal teratomas are derived from ectopic
primordial germ cells is plausible. It has been shown for man and the
mouse (Mintz, 1960) that some migrating primordial germ cells fail to
reach the gonad, and that they may become lodged in extragonadal
sites. They may constitute potential foci of teratomas.
The author (1964) transplanted the genital ridges from 12.5-day fetal
strain 129 mice to the spleens of adults, and some of them developed into
testes with teratomas. This means that teratomas will develop in abnormally located germ cells, and weakly supports the theory that extragonadal teratomas are derived from displaced germ cells. The fact that
two-celled mouse ova will develop into teratoid growths when transplanted to the adult testis (Stevens, unpublished) also weakly supports
this theory.
IX. Pathogenesis
According to Willis (1962a), nearly all teratomas including those of
the testis are congenital or originate in infancy or childhood. On the