Images in Pathology - Placental Site Trophoblastic Tumour

A 27-years-old woman married for 5 years with history of twin delivery 2¹/₂ years ago, had irregular vaginal bleeding for last 10 months. She underwent dilatation and curettage (D & C) twice which showed secretary endometrium. Her Beta-hCG values were 5632 MIU/ml and she received methotrexate for gestational trophoblastic disease. But her bleeding persisted, bhCG level reached to 8000 MIU/ml. There was a growth of 4x4 cm in uterine cavity on ultrasound and colour Doppler revealed high velocity flow. Repeat curettage depicted a picture of placental site trophoblastic tumour (PSTT) on histopathology (Figure 1). There were sheets of intermediate trophoblast with marked nuclear pleomorphism and 3-5 mitotic figures/10 high power field (HPF). No syncytiotrophoblastic cells were identified. There was diffuse positivity to cytokeratin with foci of necrosis, lymphocyte infiltration fibrin deposition and inner third myometrial invasion. Stains for bhCG and human placental lactogen (HPL) could not be done.