Invasive mole is a complication of molar pregnancy where abnormal villi grow into the myometrium or blood vessels. It occurs in approximately 15% of complete moles and can metastasize to other organs. Clinical features include persistent hemorrhage and uterine perforation. Microscopically, proliferating trophoblast tissue is seen invading the myometrium. Treatment involves chemotherapy, with single or combination drug regimens depending on the disease stage. The goals are to normalize hCG levels and administer additional "clean-up" courses of chemotherapy.

1. INVASIVE MOLEDr. Margarita Isabel Amoroso-ArtesDepartment of OB/GYN

2. DefinitionMolar pregnancy ChorioadenomaDestruensMolar villi grow into the myometrium or its blood vesselsMay extend into the broad ligament and metastasize to the lungs, the vagina or the vulva.

3. All cases of invasive mole are sequelae of hydatidiform molesApproximately 15% of complete moles are associated with or precede invasive molesThe pathologic diagnosis of invasive mole is rarely made because most cases are treated medically, without hysterectomy

4. CLINICAL FEATURESPERSISTENT HEMORRHAGEUTERINE PERFORATION

5. Vascular invasion may result in trophoblastic nodules in sites outside the uterus, such as: vaginalungs

6. Hydropicvilli covered by proliferating trophoblast are seen permeating the myometrium in this invasive mole

7. Gross appearance of invasive mole. A hemorrhagic mass has permeated half of the thickness of the myometrial wall.

8. Whole-mount view of invasive mole. Abnormal villi are seen permeating the thickened myometrium (arrows).

9. Invasive mole vs complete moleDIFFERENTIALS

10. Large villi with stromaledema and marked trophoblastic proliferationDiagnostic PearlsNearly all of the villi show hydropic degeneration appearing as a 'bunch of grapes', vesicles measure 1 to 30 mm, and no embryo, fetus , membranes or cord is seen There is vesicular swelling of the villi and hyperplasia of the trophoblastTrophoblastic hyperplasia has a circumferential arrangement around each villiAbnormal villi with proliferating trophoblast invading the myometriumDiagnostic PearlsHemorrhagic mass permeating the myometrial wall Abnormal villi are seen permeating the myometrial wall or inside blood vessels The vascular invasion may result in nodules outside the uterus

11. INVASIVE MOLE VS PARTIAL MOLEDIFFERENTIALS

12. Scalloping of the villi and pseudoinclusion of trophoblastic tissueDiagnostic PearlsLess placental tissue than in complete mole, with a mixture of normal villi and large vesicles, an embryo or a fetus may be found Mixture of large and small villi, with focal edema to cisterna formation Many of the villi have an irregular, scalloped outline and contain vessels with fetal red blood cells Abnormal villi with proliferating trophoblast invading the myometriumDiagnostic PearlsHemorrhagic mass permeating the myometrial wall Abnormal villi are seen permeating the myometrial wall or inside blood vessels The vascular invasion may result in nodules outside the uterus

13. INVASIVE MOLE VS CHORIOCARCINOMADIFFERENTIALS

14. Admixture of syncytiotrophoblast and cytotrophoblast is seen in this exampleDiagnostic PearlsClusters of cytotrophoblast separated by streaming masses of syncytiotrophoblast, with a characteristic dimophicplexiform pattern Villi formation must be absent Vascular invasion is commonly found and may be extensiveAbnormal villi with proliferating trophoblast invading the myometriumDiagnostic PearlsHemorrhagic mass permeating the myometrial wall Abnormal villi are seen permeating the myometrial wall or inside blood vessels The vascular invasion may result in nodules outside the uterus

15. Figo Staging

16. MANAGEMENTCHEMOTHERAPY PRIMARILY

17. Stage I, Stage II-III low risks patientsSingle Agent every 7- 10 days2 clean-up courses after the first normal titerDiscontinue Chemotherapy/shifted to another regimen: (actinomycin D)(+) toxicityDrug resistance

18. Stage II-III, High RiskCombination of chemotherapy q 14 days, until hCG titer is normalEMACO (Etoposide, Metothrexate, Actinomycin, Oncovin), MEA3 clean-up courses

19. Stage IV patientsInitial combination chemotherapy q 14 days3 clean up courses after the 1st normal titerIF with Brain metsIntrathecalmetothrexate12.5 mg Steroids or MannitolFor brain decompression