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GYNAECOLOGY AND OBSTETRICS IMAGING Table of Contents   
Year : 2006  |  Volume : 16  |  Issue : 4  |  Page : 819-821
Placental site trophoblastic tumor a rare type of gestational trophoblastic neoplasia


Department of Radiodiagnosis & Imaging, Gandhi Medical College & Associated Hamidia Hospital, Bhopal, India

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Date of Submission30-Apr-2006
Date of Acceptance10-Aug-2006
 

Keywords: Placental site trophoblastic tumor

How to cite this article:
Malik R, Pandya V K, Agrawal G, Jain M. Placental site trophoblastic tumor a rare type of gestational trophoblastic neoplasia. Indian J Radiol Imaging 2006;16:819-21

How to cite this URL:
Malik R, Pandya V K, Agrawal G, Jain M. Placental site trophoblastic tumor a rare type of gestational trophoblastic neoplasia. Indian J Radiol Imaging [serial online] 2006 [cited 2020 Jan 19];16:819-21. Available from: http://www.ijri.org/text.asp?2006/16/4/819/32357

   Introduction Top


Persistent trophoblastic neoplasia (PTN) is life threatening complication of pregnancy that encompasses invasive mole, choriocarcinoma and extremely rare placental site trophoblastic tumor. In difficult cases imaging may be the first to suggest diagnosis and in all cases USG and CT scan plays an important role in staging the disease.


   Case report Top


A 26 years female presented to Gynecological department with complaints of excessive vaginal bleeding for 5 months following normal term home delivery. USG abdomen was done which showed large hetrogenous pelvic mass with multiple cystic spaces filling and replacing the whole uterus with evidence of urinary bladder invasion (Fig.1). On Color Doppler a florid color mosaic pattern (Fig. 2) with a low impedance flow was seen within the cystic spaces of mass, with a peak systolic velocity is 60 cm/sec and resistive index 0.4. A diagnosis of persistent trophoblastic neoplasia (PTN) was made. HCG (Human chorionic gonadotropin) assay was done, which revealed level of HCG 1500 MIU/ml. Finally CT scan abdomen including lung bases was done to see the extension and metastasis. A highly vascular pelvic mass with extensive invasion of urinary bladder base, rectum and vagina was seen (Fig.3). Additional findings of pulmonary metastasis were found (Fig. 4). Patient was treated with intensive multi agent chemotherapy with adjuvant radiotherapy followed by hysterectomy. Histopathology revealed nodular aggregate of intermediate trophoblast s/o placental site trophoblastic tumor.


   Discussion Top


Trophoblastic tumors include a spectrum of chorionic neoplasm that may be gestational or non gestational by virtue of their high vascularity and affinity of trophoblast for blood vessel. Metastasis often occurs early and most common site of such metastasis is the lung [1].

Malignant gestational trophoblastic diseases refer to invasive mole, chorio carcinoma, and placental site trophoblastic tumor [2]. Placental site trophoblastic tumor (PSTT) is the least common form of gestational trophoblastic disease. The tumor represents neoplastic transformation of the intermediate trophoblastic cells that normally plays a critical role in implantation. PSTT can occur after a normal pregnancy, spontaneous abortion, termination of pregnancy, ectopic or molar pregnancy [3].

The most common clinical findings are irregular bleeding associated with uterine involution; hence any case of unusual bleeding should be investigated with curettage and HCG level. With the exception of PSTT, HCG is specific and sensitive marker for detecting and monitoring PTN [4]. In case of PSTT serum HCG level may be normal to high [2].

PSTT is an extremely rare tumor arising from placental implantation site and resembles an exaggerated form of surgical endometritis. Trophoblastic cells can infiltrate the myometrium, and there is vascular invasion. Human placental lactogen is present in the tumor cells, while immunoperoxidase staining for HCG is relatively low [5].

Histologically, monomorphic cell population of intermediate trophoblastic cells, invading singly or in cord and sheet are present. Blood vessel walls are extensively replaced by trophoblastic cells and fibrinoid material. Extensive necrosis may occur.

Although the imaging findings of PSTT have seldom been reported, available data indicates that it can be divided into two types, a hypervascular and a relatively hypovascular type. In hypervascular PSTT massive bleeding following dilatation and curettage have been reported. On the other hand, uterine conservative surgery is possible in patient with the localized hypovascular type. The main role of imaging diagnosis of PSTT is to clarify the vascularity of tumor [6].

Sonography is currently the best imaging modality for assessing uterine and pelvic disease in PTN. The most frequently described sonographic abnormality in PTN is a focal echogenic myometrial nodule. Lesion may appear solid and uniformly echogenic, hypoechoic, or complex and multi cystic. Anechoic area represents tissue necrosis or vascular space, while hemorrhage appears as a thick walled irregular cavity within solid tumor. Patient with PTN may also present with bulky uterine enlargement with tumor replacing the entire myometrium. The tumor mass may extend to parametrium, pelvic side wall and adjacent organs. In extreme cases, PTN appear as a large undifferentiated pelvic masses. Differential diagnosis includes benign condition like adenomyosis, fibroid, arteriovenous malformation. Duplex and Doppler feature of PTN suggest marked hypervascularity. Duplex feature shows high velocity low impendence blood flow due to functional AV shunting. Peak systolic velocity is greater than 50 cm/sec and resistive index less than 0.5. Color Doppler features typical of PTN include extensive color aliasing, admixture of color signal, loss of discreteness of vessel and chaotic vascular arrangement. When PTN is clinically unsuspected, duplex Color Doppler may provide the first indication of trophoblastic disease [4]. Anatomical staging before treatment includes pelvic examination, chest radiograph, and CT scan of abdomen and pelvis [2].

CT scan demonstrates disease that has invaded the broad ligament, parametrium, pelvic fascia and muscle. It can also evaluate hepatic, pulmonary and cerebral metastasis [7].

Hypovascular PSTT may not be diagnosed sonographically, where MRI allows accurate localization, though the findings are not specific and the diagnosis of PSTT is made from the biopsy specimen [8].

Hystrectomy is most efficacious treatment for confirmed placental site trophoblastic tumor although chemotherapy is recommended for metastatic disease.

 
   References Top

1.Natsume M, Takada J, Choricarcinoma An unusual case recurring 9 years after subtotal hysterectomy and followed by spontaneous regression of pulmonary metastases. Amj. Obstet Gynecol 1961 Sep; 82: 654-9.   Back to cited text no. 1    
2.F. Gray Cunninghum, Kenneth J, Steven L Bloom, John C. Hauth, Larry C. Gillstrap, Katherine D Wenstorm. Williams Obstetrics, 22nd ed. Mc Graw Hill, 2005:273-284  Back to cited text no. 2    
3.Colleen M. Feltmate, David R. Genest, Donald P. Goldstein, Ross S. Berkowitz, Advances in the Understanding of Placental Site Trophoblastic Tumor. J Reprod Med 2002; 47:337-341  Back to cited text no. 3    
4.Margaret A, Frase-Hill, Stephanie R. Wilson. Gestational Trophoblastic Neoplasia. IN: Carol M Rumack, Stephanie R Wilson, J. Williams Charboneau, eds.Diagnostic Ultrasound,3rd ed. St.Louis: ELSEVIER MOSBY, 2005:589-602.   Back to cited text no. 4    
5.Lurain JR, Gestational trophoblastic tumor. Semin Surg oncol 6(6): 347-53,1990  Back to cited text no. 5    
6.Sumi Y, Ozaki Y, Shindoh N, Katayama H, Placental site trophoblastic tumor: Imaging findings. Radiat Med. 1999 Nov-Dec; 17(6): 427-30.  Back to cited text no. 6    
7.John A spenser, Sarah E. Swift. Computed tomography of pelvis. In john R Hagga, Charles F. Lanzieri, Robert C. Gilkeson eds. CT and MR imaging of the whole body, 4th ed. St.Louis: Mosby, 2003: 1715-1749  Back to cited text no. 7    
8.Brandt K R, Coakley K J, MR appearance of placental site trophoblastic tumor: A report of three cases. AJR Am J Roentgenol 1998 Feb;170(2): 458-7  Back to cited text no. 8    

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Correspondence Address:
R Malik
Department of Radiodiagnosis & Imaging, Gandhi Medical College & Associated Hamidia Hospital, Bhopal
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0971-3026.32357

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    Figures

  [Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4]



 

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