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Gestational Trophoblastic Disease | Radiology Key

Gestational Trophoblastic Disease



Gestational Trophoblastic Disease


Akram M. Shaaban, MBBCh












































(T) Primary Tumor


Adapted from 7th edition AJCC Staging Forms.


TNM


FIGO


Definitions


TX


Primary tumor cannot be assessed


T0


No evidence of primary tumor


T1


I


Tumor confined to uterus


T2


II


Tumor extends to other genital structures (ovary, tube, vagina, broad ligaments) by metastasis or direct extension


(M) Distant Metastasis


M0


No clinical metastasis


M1


Distant metastases



M1a


III


Lung metastasis



M1b


IV


All other distant metastasis




























































Prognostic Scoring Index for
Gestational Trophoblastic Tumors


Risk Factors


0


1


2


4


Age


< 40 years


≥ 40 years




Antecedent pregnancy


Mole


Abortion


Term pregnancy



Interval months from index pregnancy


< 4


4-6


7-12


> 12


Pre-treatment serum hCG (IU/L)


< 103


103 to < 104


104 to < 105


≥ 105


Largest tumor size in cm


< 3 cm


3 – 5


> 5



Site of metastases


Lung


Spleen, kidney


GI tract


Brain, liver


Number of metastases



1-4


5-8


> 8


Previous failed chemotherapy




Single drug


≥ 2 drugs
















































































AJCC Stages/Prognostic Groups


Adapted from 7th edition AJCC Staging Forms.


Stage


T


M


Risk Factors


I


T1


M0


Unknown



IA


T1


M0


Low risk



IB


T1


M0


High risk


II


T2


M0


Unknown



IIA


T2


M0


Low risk



IIB


T2


M0


High risk


III


Any T


M1a


Unknown



IIIA


Any T


M1a


Low risk



IIIB


Any T


M1a


High risk


IV


Any T


M1b


Unknown



IVA


Any T


M1b


Low risk



IVB


Any T


M1b


High risk








H&E stain shows 2 key features of a complete hydatidiform mole: Trophoblastic proliferation and villous edema. Note the enlarged villus that has central cistern (entirely acellular space), stromal edema, and a circumferential proliferation of trophoblasts around the surface. (Original magnification 200x.)






H&E stain shows a mixture of enlarged, edematous villi with cisterns image and small, normal-sized villi with fibrotic stroma image. The large villi have scalloped surfaces with trophoblast infolding, forming inclusions. The trophoblastic proliferation is focal and composed of haphazard tufts of trophoblasts. (Original magnification 200x.)






High magnification of an H&E stain shows highly atypical cytotrophoblast cells with irregular hyperchromatic nuclei mixed with syncytiotrophoblasts. (Original magnification 1000x.)






H&E stain shows sheets of intermediate trophoblasts, characterized by large polygonal cells with irregular nuclei and dense eosinophilic cytoplasm. In contrast, choriocarcinoma is composed of a mixture of cytotrophoblasts, syncytiotrophoblasts, and intermediate trophoblasts. (Original magnification 1000x.)







This graphic demonstrates the uterus in the coronal plane and shows gestational trophoblastic disease that is either limited to the endometrium image or invades into the myometrium image. In T1 disease, the tumor is confined to the uterus.






A cut section of the uterus as viewed from above demonstrates gestational trophoblastic disease that is either limited to the endometrium image or invades into the myometrium image. In T1 disease, the tumor is confined to the uterus.






Coronal graphic illustrates gestational trophoblastic disease extending to the broad ligament image and involving the vagina image. Either circumstance would constitute T2 disease, in which the tumor extends outside the uterus but is limited to the genital tract.






Graphic demonstrates a cut section of the uterus as viewed from above and shows tumor extending to the broad ligament image and involving the vagina image. In T2 disease, the tumor extends outside the uterus but is limited to the genital tract.







This coronal graphic shows gestational trophoblastic disease extending to the fallopian tube image and involving the ovary image. In T2 disease the tumor extends outside the uterus but is limited to the genital tract.






Graphic demonstrates a cut section of the uterus as viewed from above and shows gestational trophoblastic disease extending to the fallopian tube image and broad ligament image. In T2 disease the tumor extends outside the uterus but is limited to the genital tract.


















image


METASTASES, ORGAN FREQUENCY


Lungs


80%


Vagina


30%


Brain


10%


Liver


10%




OVERVIEW


General Comments



  • Broad spectrum of conditions characterized by abnormal proliferation of trophoblastic tissue


Classification



  • Gestational trophoblastic disease (GTD) includes



    • Hydatidiform mole



      • Complete hydatidiform mole (CHM)


      • Partial hydatidiform mole (PHM)


    • Invasive hydatidiform mole (chorioadenoma destruens) (IHM)


    • Choriocarcinoma


    • Placental-site trophoblastic tumor (PSTT)


  • Gestational trophoblastic neoplasia (GTN) includes



    • Persistent hydatidiform mole


    • Invasive hydatidiform mole


    • Choriocarcinoma


    • Placental-site trophoblastic tumor


PATHOLOGY


Routes of Spread



  • Complete and partial hydatidiform mole



    • By definition, benign localized tumors with malignant potential


    • Confined to uterus without myometrial invasion


  • Invasive hydatidiform mole



    • CHM or PHM that invades myometrium


    • Hematogenous metastases can occur to lungs and brain


    • Vaginal metastases can occur via retrograde spread through parauterine veins


  • Choriocarcinoma



    • Highly vascular with possible hematogenous spread to lungs, brain, and liver


    • Vaginal metastases are more common than in IHM


  • Placental-site trophoplastic tumor



    • Tends to spread locally to uterus


    • Can involve lymph nodes, which is uncommon with other GTN


General Features



  • Comments



    • Gestational trophoblastic disease encompasses heterogeneous family of lesions



      • Arise from various trophoblast subpopulations


      • Different malignant potential


  • Genetics



    • CHM and IHM show diploid karyotype; completely of paternal origin in majority of patients (46,XX)



      • Single haploid sperm fertilizing ovum lacking maternal genes → duplication


      • 2 sperm fertilizing ovum lacking maternal genes


    • PHM shows triploid karyotype



      • 2 sperm fertilizing normal ovum


    • Choriocarcinoma shows many abnormal karyotypes and can follow normal pregnancy


  • Etiology



    • Most important risk factor in development of GTD is previous molar pregnancy



      • Risk increases 10x in patients with previous molar pregnancy


    • Choriocarcinoma may develop after any type of pregnancy



      • 70% develop after complete mole


      • 20% after abortion or tubal pregnancy


      • 10% after term pregnancy


  • Epidemiology & cancer incidence



    • GTD are uncommon (overall 1 in 1,000 pregnancies)



      • Incidence varies by geographical location



        • ˜ 1/2,000 pregnancies in Europe and USA


        • ˜ 1/500 pregnancies in Japan, Singapore, and Malaysia


      • Incidence varies by age



        • 2 peaks of occurrence in women (< 20 or > 40 years of age)


        • > 5x increased risk in women > 40 years


    • Choriocarcinoma is rare (1 in 20,000 pregnancies)


  • Associated diseases, abnormalities



    • Theca-lutein cysts



      • Result from ovarian hyperstimulation due to high circulating levels of β-hCG


      • Often resolve 2-4 months following molar evacuation, though regression process generally takes longer than decline in β-hCG levels


      • Occur more frequently with invasive moles and choriocarcinoma than in complete moles



        • 13.8% of complete moles


        • 57.9% of invasive moles


        • 33.3% of choriocarcinoma


    • Uterine vascular malformations



      • GTD are highly vascular and associated with uterine vascular malformations


      • Vascular malformations persist in 10-15% of patients, even after complete tumor resolution following chemotherapy


      • Majority are supplied predominantly by uterine arteries


      • 1-2% of uterine vascular malformations cause vaginal or intraperitoneal hemorrhage


Gross Pathology & Surgical Features



  • Complete hydatidiform mole



    • Large-for-dates uterus


    • Bulky mass, sometimes consisting of over 500 cc of bloody tissue


    • Classical bunch of grapes appearance



      • Large villi forming transparent vesicles of variable size (1-30 mm)


    • No normal placental tissue is apparent


    • Absent embryo or fetus


  • Partial hydatidiform mole



    • Volume of tissue is often < 300 cc


    • Only proportion of villi are vesicular


    • Presence of embryonic or fetal tissues



      • Most spontaneously abort by 20 weeks


  • Invasive hydatidiform mole



    • Pathologic diagnosis of invasive mole is rarely made because most cases are treated medically, without hysterectomy


    • All cases of invasive mole are sequelae of hydatidiform moles


    • Molar villi grow into myometrium or its blood vessels



    • May extend into broad ligament and other pelvic organs


    • Rarely metastatic



      • Metastasizes to lungs and brain


  • Choriocarcinoma



    • May arise after normal (1/25,000) or abnormal pregnancy


    • Dark red hemorrhagic mass with shaggy irregular surface


    • Usually myometrial in location but can invade into surrounding structures


  • Placental-site trophoblastic tumor



    • Rare tumor arising from placental implantation site


    • Can develop from normal pregnancy, abortion, CHM, or PHM


    • Slow growing


    • Variable in size but may present with diffuse nodular thickening of myometrium


    • Occasionally polypoid mass projecting into uterine cavity


Microscopic Pathology



  • H&E



    • Complete hydatidiform mole



      • Lack of embryonic or fetal tissues


      • Cyst-like hydropic swelling of chorionic villi


      • Diffuse trophoblastic hyperplasia


      • Disintegration and loss of blood vessels in villous core


      • Diffuse & marked trophoblastic atypia at implantation site


      • Premalignant disease



        • 16% of complete moles transform into malignant GTD


    • Partial hydatidiform mole



      • Presence of embryonic or fetal tissues


      • Focal trophoblastic hyperplasia


      • Variable, usually less intense, hydropic swelling of chorionic villi


      • Focal & mild trophoblastic atypia at implantation site


      • Premalignant disease



        • 0.5% of partial moles can transform into malignant GTD


    • Invasive hydatidiform mole



      • Molar pregnancy in which molar villi grow into myometrium or its blood vessels


      • Molar villi with trophoblasts within myometrium or at extrauterine site


    • Choriocarcinoma



      • Malignant neoplasm of trophoblastic epithelium


      • Masses and sheets of trophoblastic cells without villi invading surrounding tissue and permeating vascular spaces


      • Spread to distant sites


      • Most cases present within year of antecedent pregnancy



        • However, cases described after latent periods of up to 25 years


    • Placental-site trophoblastic tumor



      • Neoplastic proliferation of intermediate trophoblasts that invade myometrium at placental site


      • Relatively poorly vascularized


      • Serum hCG only modestly elevated due to lack of syncytiotrophoblastic tissue


IMAGING FINDINGS


Detection



  • Ultrasound



    • Complete hydatidiform mole



      • Early in pregnancy



        • Enlarged uterus filled with solid hyperechoic tissue


        • Only 56% of CHM shows cysts in 1st trimester


        • Gestational sac surrounding echogenic mass may be seen


        • Can be difficult to differentiate early CHM from retained products of conception following miscarriage


      • Late in pregnancy



        • Hydropic villi appear as multiple anechoic spaces 1-30 mm in diameter


        • Cysts become more numerous and visible in 2nd trimester


      • Low resistance arterial flow on Doppler interrogation (resistive index [RI] ≈ 0.55)


      • 5 sonographic features are more often seen with GTD compared to retained products of conception



        • Myometrial epicenter


        • Depth of myometrial invasion > 1/3


        • Placental venous lakes


        • Maximum mass dimension > 3.45 cm


        • Maximum endometrial thickness < 12 mm


      • Theca lutein cysts: Large ovaries with multiple anechoic cysts


    • Partial hydatidiform mole



      • Size of placenta depends on genetic profile



        • Large placenta with focal numerous cysts if extra paternal chromosome (69,XXY)


        • Small placenta if extra maternal chromosome (69,XXX)


      • Maintained overall shape of placenta


      • Gestational sac (GS) is present


      • Ratio of transverse to anteroposterior diameter of GS > 1.5


      • Abnormal fetus with multiple anomalies and growth restriction


    • Invasive hydatidiform mole



      • CHM with myometrial invasion


    • Choriocarcinoma



      • Uterine disease may be absent in patients with metastatic disease


      • Focally irregular, echogenic, heterogeneous regions within myometrium


      • Sonolucent areas surrounding echogenic foci correspond to myometrial hemorrhage


      • Highly vascular on Doppler US


    • Placental-site trophoblastic tumor



      • Heterogeneous hyperechoic mass with cystic changes within myometrium


      • Doppler US: Both hypervascular & hypovascular forms have been described


  • CT



    • Limited role in detection of GTD



    • Complete and partial hydatidiform mole



      • Heterogeneously enhancing endometrial mass


      • Reticular pattern of enhancement between low-signal vesicles


    • Invasive hydatidiform mole



      • Similar to hydatidiform mole with myometrial invasion


    • Choriocarcinoma and PSTT



      • Myometrial mass ± endometrial component


      • Heterogeneous enhancement with prominent enhancing vessels


  • MR

Sep 18, 2016 | Posted by in OBSTETRICS & GYNAECOLOGY IMAGING | Comments Off on Gestational Trophoblastic Disease
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