4
LEROY C. STEVENS
1950), Peterson et al. (1955), and Abell et al. (1963, 1965). Willis and
Rudduck (1943) described teratomas in horses, and teratomas in guinea
pigs have been described by Ponse et al. (1954), Mosinger (1961), and
Willis (1962b). Guthrie (1964) and Bresler (1964) cited all of the important literature dealing with testicular teratomas in fowl. Teratomas
have been found in the guppy and lizard (Stolk, 1958, 1959). Stolk
believed that the stimulus for the development of the unfertilized oocytes
was a local parasitic infection. Ovarian teratomas in the mouse have been
described by Jackson and Brues (1941), Fawcett (1950a), Fekete and
Ferrigno (1952), and Thiery (1963). Mouse testicular teratomas were
described by Stevens et al. (1954, 1957, 1962). Dunn and Andervont
(1963) described a teratoma on the side of the face and in the mesentery
of a 10-week-old wild male mouse. It contained fetal nervous tissue,
mucous and squamous epithelial cysts, cartilage, and bone with marrow.
They thought it likely that the tumor may have started during fetal life.
This is the only report of multiple extragenital teratoid tumors in mice.
The number of species in which teratomas have been described is
small. Teratomas have never been reported in such well-investigated
animals as the dog, rat, and rabbit. Other than the testicular teratomas
that occur in high incidence in strain 129 mice, the only other case of
spontaneous testicular teratoma is one the author observed in a strain
A/He mouse. From 19,000 autopsies of mice, Slye (1919) found 28
instances of primary tumors of the testis, and none of them were
teratoid. She remarked, "It is a matter of comment that we have found
no example of the teratoid type of tumor that is so common in humans."
B. Influence of Sex and Age
The growth and differentiation of teratomas is profoundly affected by
the sex of the bearer. For example, ovarian teratomas or dermoid cysts
are common in human females and they are usually benign (Willis,
1962a; Peterson et al. 1955; Dixon and Moore, 1953; Neubecker and
Breen, 1962; Abell et al. 1965). In contrast, the homologous tumor in
human males is rare and usually highly malignant. In human beings,
benign ovarian teratomas occur 100 times more frequently than benign
testicular teratomas (Mathé, 1957). Abell et al. (1965) found only six
benign cystic teratomas of the testis compared with 72 of the ovary. They
found that malignant germ cell neoplasms of gonads were more frequent
in infant males than in females.
Some teratomas can be detected in newborns, and it can be categorically stated that a teratoma discovered in the testis of an adult is much
more likely to be malignant than one occurring in a child (Abell and
Holtz, 1963).
Tumors of the testis occur most frequently in the young adult male
LEROY C. STEVENS
1950), Peterson et al. (1955), and Abell et al. (1963, 1965). Willis and
Rudduck (1943) described teratomas in horses, and teratomas in guinea
pigs have been described by Ponse et al. (1954), Mosinger (1961), and
Willis (1962b). Guthrie (1964) and Bresler (1964) cited all of the important literature dealing with testicular teratomas in fowl. Teratomas
have been found in the guppy and lizard (Stolk, 1958, 1959). Stolk
believed that the stimulus for the development of the unfertilized oocytes
was a local parasitic infection. Ovarian teratomas in the mouse have been
described by Jackson and Brues (1941), Fawcett (1950a), Fekete and
Ferrigno (1952), and Thiery (1963). Mouse testicular teratomas were
described by Stevens et al. (1954, 1957, 1962). Dunn and Andervont
(1963) described a teratoma on the side of the face and in the mesentery
of a 10-week-old wild male mouse. It contained fetal nervous tissue,
mucous and squamous epithelial cysts, cartilage, and bone with marrow.
They thought it likely that the tumor may have started during fetal life.
This is the only report of multiple extragenital teratoid tumors in mice.
The number of species in which teratomas have been described is
small. Teratomas have never been reported in such well-investigated
animals as the dog, rat, and rabbit. Other than the testicular teratomas
that occur in high incidence in strain 129 mice, the only other case of
spontaneous testicular teratoma is one the author observed in a strain
A/He mouse. From 19,000 autopsies of mice, Slye (1919) found 28
instances of primary tumors of the testis, and none of them were
teratoid. She remarked, "It is a matter of comment that we have found
no example of the teratoid type of tumor that is so common in humans."
B. Influence of Sex and Age
The growth and differentiation of teratomas is profoundly affected by
the sex of the bearer. For example, ovarian teratomas or dermoid cysts
are common in human females and they are usually benign (Willis,
1962a; Peterson et al. 1955; Dixon and Moore, 1953; Neubecker and
Breen, 1962; Abell et al. 1965). In contrast, the homologous tumor in
human males is rare and usually highly malignant. In human beings,
benign ovarian teratomas occur 100 times more frequently than benign
testicular teratomas (Mathé, 1957). Abell et al. (1965) found only six
benign cystic teratomas of the testis compared with 72 of the ovary. They
found that malignant germ cell neoplasms of gonads were more frequent
in infant males than in females.
Some teratomas can be detected in newborns, and it can be categorically stated that a teratoma discovered in the testis of an adult is much
more likely to be malignant than one occurring in a child (Abell and
Holtz, 1963).
Tumors of the testis occur most frequently in the young adult male