Page 767 - Textbook of Pathology, 6th Edition

 TABLE 24.7: FIGO Clinical Staging of Carcinoma of the Ovary. Certain conditions such as inflammation of the placenta and 751
chorionic membranes (placentitis and chorioamnionitis),
Stage I Growth limited to ovaries. placental abnormalities (e.g. placenta accreta, placenta
IA Growth limited to one ovary; no ascites; capsule praevia and twin placenta etc), toxaemia of pregnancy
intact.
IB Growth limited to both ovaries; no ascites; capsule (eclampsia and pre-eclampsia) and products of gestation seen
intact. in abortions need mere mention only here. However,
IC Tumour classified as either stage IA or IB but with gestational trophoblastic diseases resulting from benign
tumour in the surface of one or both ovaries, or with and malignant overgrowth of trophoblast—hydatidiform
ascites containing malignant cells. mole (complete and partial mole) and choriocarcinoma
Stage II Growth involving one or both ovaries, with pelvic respectively, are significant morphologic lessions and are
extension. discussed below and their features contrasted in Table 24.8.
IIA Extension and/or metastases to the uterus and/or
tubes. HYDATIDIFORM MOLE
IIB Extension to other pelvic tissues.
IIC Tumour either stage IIA or IIB but with tumour on the The word ‘hydatidiform’ means drop of water and ‘mole’ for
surface of one or both ovaries, or with capsule a shapeless mass. Hydatidiform mole is defined as an abnormal
ruptured, or with ascites containing malignant cells. placenta characterised by 2 features:
Stage III Tumour invading one or both ovaries with peritoneal i) Enlarged, oedematous and hydropic change of the
implants outside the pelvis. chorionic villi which become vesicular.
IIIA Tumour grossly limited to the true pelvis with negative ii) Variable amount of trophoblastic proliferation.
nodes but with microscopic seeding of abdominal Most workers consider hydatidiform mole as a benign
peritoneal surfaces.
IIIB Tumour of one or both ovaries with histologically tumour of placental tissue with potential for developing into
confirmed implants of abdominal peritoneal surfaces, choriocarcinoma, while some authors have described mole
not exceeding 2 cm in diameter; nodes are negative. as a degenerative lesion though capable of neoplastic change.
IIIC Abdominal implants greater than 2 cm in diameter The incidence of molar pregnancy is high in teenagers and
and/or positive retroperitoneal or inguinal nodes. in older women. For unknown reasons, frequency of
Stage IV Growth involving one or both ovaries, with distant hydatidiform mole varies in different regions of the world; CHAPTER 24
metastases.
the incidence in Asia and Central America is about 10 times
higher than in the United States. The incidence is higher in
PLACENTA poorer classes.
Hydatidiform mole may be non-invasive or invasive. Two
NORMAL STRUCTURE types of non-invasive moles are distinguished—complete
(classic) and partial. Pathogenesis of these 2 forms is different:
At term, the normal placenta is blue red, rounded, flattened
and discoid organ 15-20 cm in diameter and 2-4 cm thick. It Complete (classic) mole by cytogenetic studies has been
weighs 400-600 gm or about one-sixth the weight of the shown to be derived from the father (androgenesis) and has
newborn. The umbilical cord is about 50 cm long and 46, XX or rarely 46, XY chromosomal pattern. Complete mole
contains two umbilical arteries and one umbilical vein bears relationship to choriocarcinoma. The Female Genital Tract
attached at the foetal surface. The placenta is derived from Partial mole is mostly triploid (i.e. 69,XXY or 69,XXX)
both maternal and foetal tissues. The maternal portion of the and rarely tetraploid. Partial mole rarely develops into
placenta has irregular grooves dividing it into cotyledons choriocarcinoma.
which are composed of sheets of decidua basalis and Clinically, the condition appears in 4th-5th month of
remnants of blood vessels. The foetal portion of the placenta gestation and is characterised by increase in uterine size,
is composed of numerous functional units called chorionic vaginal bleeding and often with symptoms of toxaemia.
villi and comprise the major part of placenta at term. The Frequently, there is history of passage of grape-like masses
villi consist of a loose fibrovascular stromal core and a few per vaginum. About 1% of women with molar pregnancy
phagocytic (Höffbauer’s) cells. The villous core is covered develop it again in a subsequent pregnancy.
by an inner layer of cytotrophoblast and outer layer of The single most significant investigation forming the
syncytiotrophoblast. The basement membrane separating mainstay of management is the serial determination of
the foetal capillaries in the villous core and the trophoblast β-hCG which is elevated more in both blood and urine as
forms zones where nutrients and metabolites are compared with the levels in normal pregnancy. Removal of
transported between the mother and the foetus. Such zones the mole is accompanied by fall in β-hCG levels. A more
are called vasculosyncitial membranes. The placenta ominous behaviour is associated with no fall in β-hCG
secretes a number of hormones and enzymes into the levels after expulsion of the mole. About 10% of patients with
maternal blood. These include: human chorionic gonado- complete mole develop into invasive moles and 2.5% into
tropin (hCG), human placental lactogen (HPL), chorionic choriocarcinoma.
thyrotropin and adrenocorticotropin hormone which
partake in oestrogen and progesterone metabolism. MORPHOLOGIC FEATURES. The pathologic findings
Diseases related to pregnancy and placenta are numerous in non-invasive (complete and partial) and invasive mole
and form the subject matter of discussion in obstetrics. are different: