A rare case of placental site trophoblastic tumor

Abstract

Placental site trophoblastic tumor (PSTT) is a very rare tumor of young women and unique form of gestational trophoblastic disease (GTD) representing a neoplastic transformation of intermediate trophoblastic cells that play a critical role in implantation. It accounts for 1-2% of all GTNs, incidence of it being 1 in 1,00,000 pregnancies. It displays a wide clinical spectrum from benign lesion within uterus to highly metastatic features with widespread features of metastasis and can be difficult to control even with surgery and chemotherapy. Unlike other forms of GTD, it is characterized by low β-hCG levels because it is a neoplastic proliferation of intermediate trophoblastic cells. PSTT can develop following all kind of pregnancies, whereas approximately 50% of PSTT cases occur after a normal pregnancy and other cases follow abortion, term delivery, ectopic pregnancy and molar pregnancy. Histopathologically, PSTT has proliferation of intermediate trophoblastic cells and absence of villi. It shows less invasion of vascular tissue and using immune histochemistry revealed that PSTT cells expressed HPL more than β-hCG, characterized by increased expression of the HPL in histological section as well as serum. The most common presenting symptoms of PSTT are irregular vaginal bleeding associated with uterine sub involution. Patient can also be presented with amenorrhea, nephritic syndrome, abdominal pain, galactorrhea and hemoptysis. Hence any case of unusual bleeding should be investigated with dilation and curettage and βHCG levels. Although the majority of patients of the non-metastatic PSTT are cured by hysterectomy but in metastatic cases, it requires aggressive treatment with chemotherapy and radiation. Due to its seldom occurrence and uncharacteristic clinical presentation, to reach a correct diagnosis and management is a surgeon’s nightmare and can be very challenging.