Book of Medical Disorders in Pregnancy - Tintash

cause progressive renal failure as the
cysts become larger and the functioning
renal parenchyma smaller in volume.
This is the "Type III" cystic disease in
the Potter classification, but it is rarely
manifested prenatally or in children.
Cystic change with obstruction:
In the fetus and newborn with urinary
tract obstruction, it is possible for cystic
change to occur in the kidneys, in
addition to hydroureter, hydronephrosis,
and bladder dilation. Depending upon
the point of obstruction, either or both
kidneys may be involved. For example,
posterior urethral valves in a male fetus,
or urethral atresia in a male or female
fetus, will cause bladder outlet obstructtion
so that both kidneys are involved.
With bladder outlet obstruct-tion, there
will be oligohydramnios and the appearance
of pulmonary hypoplasia. N
Grossly, this form of cystic disease may
not be apparent. The cysts may be no
more than 1 mm in size. Microscopically,
the cysts form in association with the
more sensitive developing glomeruli in
the nephrogenic zone so that the cysts
tend to be in a cortical location. Thus,
"cortical microcysts" are the hallmark of
this form of cystic disease, which is
"Type IV" in the Potter's classification.
There are no accompanying cystic
changes in other organs in association
with this disease.
Congenital neoplasms: Such tumors are
uncommon, but those that are seen most
frequently include: Teratoma. These
tumors occur in midline regions
(sacrococcygeal, cerebral, and nasopharyngeal).
Nasopharyngeal teratoma, gross:
Tera-toma, low power microscopic
and immature teratoma, medium power
microscopic. Hemangioma. About 1/3 of
all soft tissue neoplasms in the first year
203
of life are hemangiomas or
lymphangiomas. Fibromatoses are also
comon. Hemangioma, gross and Hemangioma,
microscopic. Neuroblastoma.
The incidence of congenital neuro-blastoma
is 1:8000. Neuroblastoma, gross.
Neuroblastoma, microscopic. Size and
location are important, for even histologically
benign neoplasms can obliterate
normal tissues, be difficult to resect, or
recur with incomplete resec-tion. Malignant
neoplasms have the capacity for
invasion and metastases.
Skeletal abnormalities:
Ultrasound may reveal long bones that
are short-ened. There are several possibilities,
including short limbed dwarfism,
osteogenesis imperfecta, and short
rib polydactyly syndrome. The various
forms of short limbed dwarfism, which
can be lethal, are more difficult to
diagnose specifically. The features of
these various conditions may not be well
developed at 20 weeks gestation or less,
making diagnosis more difficult. Limitation
of survival is often due to pulmonary
hypoplasia because the chest cavity
is too small. Achondroplasia is a form of
short-limbed dwarfism that is inherited
in an autosomal dominant fash-ion,
though in most cases there is no affected
parent and the disease is due to a new
mutation. The homozygous form of the
disease is lethal. The heterozygous form
is not lethal, and affected persons can
live a normal life. They have short
extremities, but a relatively normal sized
thorax and normal sized head. Thanatophoric
dysplasia (TD) is a lethal condition.
The long bones are short and curved,
with femora that have a "teleph-one
receiver" appearance on radiograph because
of the curvature. The vertebrae