6
LEROY C. S T E V E N S
IV. Composition
The composition of teratomas is highly variable. Some are simple,
containing little more than neural tissue or undifferentiated embryonaltype cells. Others contain almost all kinds of tissues. In the mouse,
neural tissue is the predominant component in testicular teratomas, and
it is present in all primary teratomas of strain 129 mice. Notochord is
present in 97% of them. Respiratory, alimentary, and glandular epithelia
are present in most teratomas. Skin with hair and sebaceous glands is
present in 7%. Most contain cartilage and bone with marrow (Fig. 1).
FIG. 1. Spontaneous testicular teratoma in an adult strain 129 mouse. At the top
is an epithelial cyst; mid-left, neural tissue; mid-right, bone with marrow and
cartilage; bottom, a patch of notochord containing a spicule of bone. X 100.
Many have smooth, striated, and cardiac muscle. Adipose tissue is common. Adrenal and thyroid cells are occasionally seen (Stevens and
Hummel, 1957).
According to Willis (1962a) it is doubtful if notochord or cardiac
muscle have ever been demonstrated in human teratomas. Notably absent
from teratomas are any tissues resembling liver, kidney, or gonads
(Jackson and Brues, 1941). I have histologically examined thousands
of teratomas of strain 129 mice and none contained liver or kidney, and
only one contained a fetal testis (Figs. 2 and 3). Primordial germ cells
LEROY C. S T E V E N S
IV. Composition
The composition of teratomas is highly variable. Some are simple,
containing little more than neural tissue or undifferentiated embryonaltype cells. Others contain almost all kinds of tissues. In the mouse,
neural tissue is the predominant component in testicular teratomas, and
it is present in all primary teratomas of strain 129 mice. Notochord is
present in 97% of them. Respiratory, alimentary, and glandular epithelia
are present in most teratomas. Skin with hair and sebaceous glands is
present in 7%. Most contain cartilage and bone with marrow (Fig. 1).
FIG. 1. Spontaneous testicular teratoma in an adult strain 129 mouse. At the top
is an epithelial cyst; mid-left, neural tissue; mid-right, bone with marrow and
cartilage; bottom, a patch of notochord containing a spicule of bone. X 100.
Many have smooth, striated, and cardiac muscle. Adipose tissue is common. Adrenal and thyroid cells are occasionally seen (Stevens and
Hummel, 1957).
According to Willis (1962a) it is doubtful if notochord or cardiac
muscle have ever been demonstrated in human teratomas. Notably absent
from teratomas are any tissues resembling liver, kidney, or gonads
(Jackson and Brues, 1941). I have histologically examined thousands
of teratomas of strain 129 mice and none contained liver or kidney, and
only one contained a fetal testis (Figs. 2 and 3). Primordial germ cells