THE EMBRYOLOGY AND ETIOLOGY OF
TUMOURS 83
each
and every primary germ-cell (those of the ovary and testis, of course,
included) possesses the faculty of that primary germ-cell, which unfolded as an
embryo, of doing likewise.
Of
great significance with reference to the question of the germ-cell origin of
tumours are the comparatively frequent instances of tumours arising in multiple
centres. Some of the recorded cases may be cited from Borst (loc. cit., p.
57, A, et seq.). In the same individual, tumours have been found in
liver, uterus, ovary, kidney, skin, etc.; or, again, in the paired organs of
the two sides. Babesiu found in the uterus, in the middle of a myoma, a
columnar epithelial cancer, and Niebergall recorded a complicated uterine
tumour of myoma, polypes, sarcoma, and cancer. Equally important and
significant to the embryologist are the facts relating to the occasional
presence of different tumours at the same time in different parts of the body.
Borst (loc. cit., p. 58) gives the following instances:
1. Cancer of the stomach with ovarial cystoma
and fibroma of uterus.
2. Cancer of skin and of rectum.
3. A teratoid of the cranial cavity and an
ovarian embryoma.
4. Uterine myoma, lipoma of kidney, enchondroma
of lung.
5. Cancer of the thyroid, and multiple
fibromata of kidney and uterus, with large papillomata of skin.
Borst
looks upon all these and other recorded cases as accidental! They are
interesting, however, in the light of—(1) the hypothetical germ-shuntings; (2)
the various places in which vagrant germ-cells may be found, and (3) the
probable necessity of a certain physiological condition or nidus for the
development and growth of a tumour of a certain character.