Ultrastructure of molar trophoblast. Observations on hydatidiform mole and chorioadenoma destruens.

The ultrastructure of molar trophoblast is described in hydatidiform mole and chorioadenoma destruens. Villous molar trophoblast exhibits only minor deviations from normal early villous trophoblast. Invasive trophoblast of chorioadenoma destruens shows features of more-active cell growth, multiplication, differentiation, and degradation. Evidence for evolution of highly differentiated syncytial trophoblast via intermediate stages from primitive undifferentiated cytotrophoblast is confirmed. Cytoplasmic inclusions resembling virus-like particles, observed in chorioadenoma destruens, have not been hitherto described in normal or pathologic trophoblast.

[AgNOR of gastational trophoblastic tumors and its clinical significance].

A total of 120 paraffin-embedded gestational trophoblastic tumor tissue blocks was selected and divided into 5 groups: (1) 20 cases of normal chorionic villi. (2) 40 cases of hydatidiform mole with no malignant change during a following-up period of at least two years. (3) 40 cases of hydatidiform mole which developed into invasive mole or choriocarcinoma. (4) 10 cases of invasive mole. (5) 10 cases of choriocarcinoma. Nucleolar organizer regions (NORs) was Ag-stained and AgNOR dots were counted using the Plotion's method. The result showed that there was significant difference between group 1 and group 2 (P < 0.005), group 2 and group 3 (P < 0.001), group 3 and group 4 (P < 0.05). Taking the AgNOR count 4.00 as a standard, 75% of the cases in group 2 (mean = 2.730) was below this standard. The study suggested that with the increase of malignancy of trophoblastic tumor, the AgNOR count increased correspondingly. A quantitative study of AgNOR might be a useful measure to detect the early malignant change of hydatidiform mole.

[The ultrastructure of intermediate type trophoblast cell].

Transmission electron microscopy was used to clarify the detailed morphology of the "intermediate type" trophoblast cell in normal and tumor issue. 67 normal placental villi specimen, 10 placental bed specimens and 10 malignant mole, 10 hydatidiform mole, 5 choriocarcinoma specimen (the last three types taken before chemotherapy) were examined. Results showed that the transitional type trophoblasts of the placenta were developed from cytotrophoblasts through differentiation and fusion to syncytiotrophoblasts which showed features of maturation and aging, having features of cytotrophoblast nuclei and syncytiotrophoblast cytoplasm. The transitional trophoblast of placental bed showed similar morphology as that of transitional type cells of villi. The morphology of transitional type cells of villi. The morphology of transitional type cells of trophoblastic tumors had both normal morphology and cellular hyperplasia, atypia and features of tumor ultrastructure. The prominent feature was the high electron density of the granules and polymorphic cysts crowded in villi, demonstrating that the morphology of "intermediate type" trophoblasts in placental and tumor tissue are similar, whereas heterotype cellular morphology is present in varying degrees in tumor tissue.