Placental site trophoblastic tumour.
N Agarwal, Parul, A Kriplani, M Vijayaraghavan
Department of Obstetrics and Gynaecology, All India Institute of Medical Sciences New Delhi, India., India
Department of Obstetrics and Gynaecology, All India Institute of Medical Sciences New Delhi, India.
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Agarwal N, Parul, Kriplani A, Vijayaraghavan M. Placental site trophoblastic tumour. J Postgrad Med 2002;48:211-2
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Agarwal N, Parul, Kriplani A, Vijayaraghavan M. Placental site trophoblastic tumour. J Postgrad Med [serial online] 2002 [cited 2023 Jun 8 ];48:211-2
Available from: https://www.jpgmonline.com/text.asp?2002/48/3/211/101
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, ?hCG 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 ?hCG and human placental lactogen (HPL) could not be done.
On failure to respond to methotrexate, total abdominal hysterectomy was done. Both the ovaries were normal. On cut section of uterine endometrial cavity was partly filled by firm polypoidal mass of 3.5 x 2.5 x 2 cm, arising from fundus, similar nodule of 0.5 x 0.05cm was there at internal os [Figure:2]. Myometrium was superficially infiltrated. Histological features were consistent with PSTT.
Placental site trophoblastic tumour (PSTT) is the rarest variant of gestational trophoblastic disease which differs histologically, and immunochemically from gestational choriocarcinoma. Though considered a disease of reproductive age, reports have shown detection of PSTT even up to age of 66 years. It can occur as early as 1 week or as late as 17 years after abortion, normal delivery or molar pregnancy. Vaginal bleeding, is the most common symptom; it can present with amenorrhoea, galactorrhoea, nephrotic syndrome or just raised serum ?hCG .
Diagnosis of PSTT is often difficult and delayed. Histopathology of curettings is equivocal many times and so diagnosis is not recognised until operation. In equivocal case intense HPL positively, ultrastructural image and determination of HPL with ?hCG are recommended. Median concentration of ?hCG has been reported as 191 mIU/ml (range 33-20710MIU/ml).
Up to 10% of cases have been reported to have metastasis outside the uterus at presentation. High mitotic index i.e. mitotic figures >5/10 HPF is reported to be associated with increased incidence of metastatic disease.
The clinical behaviour of PSTT varies and prediction of its biological behaviour remains difficult. WHO prognostic scoring system also doses not correlate well with clinical course of PSTT. However poor prognostic factors are an internal of >2 years from known antecedent pregnancy, mitotic count >5/10 HPF, extensive necrosis and extension outside the uterus. But tumour size, depth of myometrial involvement and vascular involvement do not seem to be predictors of outcome. Risk of death is reported 14 times greater if mitotic figures were greater than 5/10 HPF. High mitotic index is associated with not only metastatic disease but appears to be an indicator of recurrence too.
Generally poor response to chemotherapy is reported and all cases ultimately undergo hysterectomy. But now complete long term remission is reported with multiagent chemotherapy in cases of PSTT. Chemotherapy is usually reserved for postoperative recurrence and those with high mitotic index.
The possibility of PSTT should be kept in mind in cases with GTD who fail to show a fall in ?hCG after chemotherapy. Since disease has an unpredictable course and poor response to chemotherapy simple hysterectomy remains the mainstay of treatment.