ABSTRACT
Nowadays valid classification of gestational trophoblastic disease, according to the World Health Organisation from the year 2003, divides gestational trophoblastic disease into three groups - molar pregnancies, non-neoplastic non-molar changes of trophoblast and tumours of trophoblast. To the molar pregnancies belong complete, partial, invasive and metastatic hydatidiform mole. In the differential diagnosis it is important to distinguish the complete hydatidiform mole from other forms of gestational trophoblastic disease, because there is an increased risk of malignant transformation of trophoblast cells in complete hydatidiform mole. 10 cases of genetically confirmed diploid complete mole and 10 cases of genetically confirmed triploid partial mole were included into our retrospective study. All cases were examined microscopically in the basic haematoxillin and eosin staining and immunohistochemically with the use of antibodies against human choriogonadotropin hormone, placental alkaline phosfatase and protein p57. Villous cytotrophoblast, stromal villous cells, extravillous trophoblast and decidual cells were p57 positive in all cases of partial hydatidiform mole. All 10 cases of complete hydatidiform mole were p57 negative in stromal villous cells and villous cytotrophoblast. P57 protein is a marker distinguishing complete hydatidiform moles from partial moles.