Gestational Trophoblastic Disease: a Histopatholgical Romp Through

Problematic Pathologies of Neoplastic Placentation

Matthew Cesari, MD, CM, FRCPC Gynecologic Pathologist, Sunnybrook Health Sciences Centre Assistant Professor, University of Toronto

March 13, 2016 OBJECTIVES

• To describe key concepts in placentation;

• To relate these concepts to the classification of non-molar gestational trophoblastic disease;

• To develop an approach to the diagnosis of non-molar gestational trophoblastic disease. Basic Concepts in Placentation

Fertilization

Robboy, 2nd Ed. Basic Concepts in Placentation

IMPLANTATION (DAYS 6-11)

Fertilization

Robboy, 2nd Ed. Basic Concepts in Placentation

IMPLANTATION (DAYS 6-11) and NIDATION

Fertilization

Robboy, 2nd Ed.

Cytotrophoblast (trophoblastic stem cell) Proliferation of pre-villous trophoblast:

Syncytiotrophoblast (Villous) Intermediate (terminally differentiated) trophoblast Basic Concepts in Placentation

IMPLANTATION NIDATION (pre-villous trophoblast)

Fertilization MESENCHYMAL VILLOUS FORMATION Courtesy: Dr. K. Grondin Basic Concepts in Placentation FERTILIZATION IMPLANTATION NIDATION (pre-villous trophoblast)

MESENCHYMAL VILLOUS FORMATION

PRIMARY VILLI

CHORION FRONDOSOM CHORION LAEVE (“placental disk”) (“membranes”)

IMPLANTATION OXYGENATION (“anchoring”) Basic Concepts in Placentation FERTILIZATION IMPLANTATION NIDATION (pre-villous trophoblast)

MESENCHYMAL VILLOUS FORMATION

PRIMARY VILLI P L Chorion A frondosum C E Primary villi N Chorion T laeve A VIT Implantation-type intermediate C Villous Intermediate trophoblast Trophoblast Chorionic-type S Intermediate trophoblast Implantation

Anchoring cell columns of villous intermediate trophoblast

Loss of E-cadherin Loss of Ki-67

Gain of hPL Gain of Mel-CAM (CD146) Gain of p57 Implantation-type intermediate trophoblast Anchoring cell columns of villous intermediate trophoblast Myometrial Invasion Loss of E-cadherin Loss of Ki-67

Gain of hPL Gain of Mel-CAM (CD146) Gain of p57 Implantation-type intermediate trophoblast Gain of E-cadherin Gain of VEGFR Vascular Invasion FUSION OF ATROPHIED VILLI/RETAINED TROPHOBLAST WITH DECIDUA OF OPPOSITE Chorion Laeve SIDE OF ENDOMETRIAL CAVITY (“membranes”) ATROPHY OF VILLOUS STROMA WITH RETENTION OF TROPHOBLAST

FUSION OF PRIMARY VILLI

PRIMARY VILLI

Blaustein, 6th Ed. Chorion Laeve

Atrophic villus Decidua Blaustein, 6th Ed. Fusion of primary villi with villous intermediate trophoblast

Gain of PlAP Gain of p63

EPITHELIAL FUNCTION

Chorionic type intermediate th trophoblast of membranes Blaustein, 6 Ed. Basic Concepts in Placentation FERTILIZATION IMPLANTATION NIDATION (pre-villous trophoblast)

MESENCHYMAL VILLOUS FORMATION

PRIMARY VILLI

CHORION FRONDOSOM CHORION LAEVE (“placental disk”)

IMPLANTATION OXYGENATION (“anchoring”)

DIAGNOSING TROPHOBLASTIC NEOPLASIA: 1) LINEAGE OF TROPHOBLAST (DIFFERENTIATION); 2) PROLIFERATIVE ACTIVITY. GESTATIONAL TROPHOBLASTIC NEOPLASIA Lancet Oncol 2007;8:642-50 CYTOTROPHOBLAST Am J Surg Pathol 2007;31:1726-1732

VILLOUS INTERMEDIATE SYNCYTIOTROPHOBLAST TROPHOBLAST

(Extravillous) (Extravillous) Implantation site intermediate Chorionic intermediate trophoblast trophoblast - Exaggerated placental site - Placental site nodule NEOPLASTIC CYTOTROPHOBLAST STEM CELL

CHORIOCARCINOMA (arrest at nidation/pre-villous stage)

PLACENTAL SITE TROPHOBLASTIC TUMOUR EPITHELIOID TROPHOBLASTIC TUMOUR (maturation to implantation) (maturation to chorion) MIXED TUMOURS CASE 1

28 F

G1P0A1(spontaneous abortion)

Spotting 3 months following evacuation hCG: 170 000 mIU/mL

Gestational Choriocarcinoma

Am J Surg Pathol 2007;31:1726-32

Definition:

Malignant epithelial tumour of predominantly intermediate and syncytial trophoblast – with a minor component of cytotrophoblast – showing morphological arrest of differentiation at the pre-villous Robboy, 2nd Ed. stage of placental development NIDATION (“nidation”). Gestational Choriocarcinoma

Clinically: - Bleeding - HCG > 10 000 - Thyrotoxicosis - Hyperreactio luteinalis (bilateral theca-lutein cysts) - Hemorrhage (brain, lung, liver, GI, etc) - Lower risk of pelvic LN mets (vs. germ cell vs. PSTT/ETT)

Antecedent gestation:

Pre-chemo era: - 50% complete hydatidiform mole Br Med J - 25% spontaneous abortion 1969;3:733-37 (probably undiagnosed early complete moles) - 22.5% term delivery (occult “in situ”?) and ectopic - <2.5% partial hydatidiform moles

Modern day: - 50% term pregnancy Obstet Gynecol - 25% complete hydatidiform mole 2006;108:176-87 Gestational Choriocarcinoma

Time to presentation: - Soon post gestation; up to 10-14 years post gestation

Genetics: - 75% show amplification of 7q21-q31 - 75% loss of 8p12-p21 - Usually 46XX - 2 cases gynogenetic (Cancer Res 1990;50:488-91)

Gestational Choriocarcinoma Therapy Am J Obstet Gynecol 2011;204:11-18 LOW RISK DISEASE: (WHO SCORE < 7)

SINGLE-AGENT CHEMOTHERAPY (methotrexate or actinomycin-D)

Cure rate >90% 20% develop resistance to initial drug; 90% salvage rate with alternate single-agent Gestational Choriocarcinoma Therapy Am J Obstet Gynecol 2011;204:11-18 HIGH RISK DISEASE: (WHO SCORE >/= 7) MULTI-AGENT CHEMOTHERAPY (EMA-CO or EMA-EP)

Cure rate approaches 80-90%

30% recurrence overall

Salvage rates for metastasis to:

Brain: 75% Liver: 73% GI: 50% Courtesy: Dr. R. Soslow B-hCG

Courtesy: Dr. R. Soslow Courtesy: Dr. R. Soslow Courtesy: B-hCG Dr. R. Soslow Ki-67 Courtesy: Dr. R. Soslow

Intraplacental (“in situ”) Choriocarcinoma

- Mimics infarct grossly and microscopically (abundant fibrin)

- Villous morphology preserved

- Villi surrounded by choriocarcinoma

Risk of disseminated maternal and fetal choriocarcinoma!!

Gynecol Oncol 2006;103:1147-51 nd Int J Gynecol Pathol 2012;32:71-5 Robboy, 2 Ed. Chorangiocarcinoma

ONLY CASE REPORTS: Possibly neoplastic proliferation of trophoblast in association with vascular placental proliferation Trophoblastic proliferation

+

Chorangiosis / Chorangioma

Robboy, 2nd Ed. ?Chorangioma + trophoblastic hyperplasia ?Trophoblastic neoplasia + reactive No clinically malignant outcome to date. chorangiosis ?Reactive trophoblast and reactive chorangiosis Placenta 2012;33:658-61 ?Collision tumour Int J Gynecol Pathol 2009;28:267-71 Virchows Arch 2000;436:167-71 Placenta 1988;9:607-13 Basic Concepts in Placentation

FERTILIZATION IMPLANTATION NIDATION (pre-villous trophoblast) Choriocarcinoma: - Classical - “Monomorphic”/Atypical MESENCHYMAL VILLOUS FORMATION - Intraplacental (‘in situ’)

PRIMARY VILLI

CHORION FRONDOSOM CHORION LAEVE (“placental disk”) Placental site nodule

IMPLANTATION OXYGENATION (“anchoring”) Legend: Non-neoplastic anatomic rests Exaggerated Placental Site Malignant Basic Concepts in Placentation

FERTILIZATION IMPLANTATION NIDATION (pre-villous trophoblast) Choriocarcinoma: - Classical - “Monomorphic”/Atypical MESENCHYMAL VILLOUS FORMATION - Intraplacental (‘in situ’)

PRIMARY VILLI

CHORION FRONDOSOM “Chorangiocarcinoma” CHORION LAEVE (“placental disk”) Placental site nodule

IMPLANTATION OXYGENATION (“anchoring”) Legend: Non-neoplastic anatomic rests Exaggerated Placental Site Malignant Misunderstood kid

CASE 2

28F

G1P1 (normal baby girl)

Baby and mother well

2 years post delivery: spotting and microscopic hematuria hCG: 104 mIU/mL; ultrasound normal

Ki-67 Placental Site Trophoblastic Tumour

Definition: Trophoblastic neoplasm showing differentiation toward implantation- type intermediate trophoblast.

Clinical: - Women of reproductive age (20 to 63 years; mean 30 years) - Amenorrhea or abnormal bleeding - Mean of 34 months post pregnancy - Low level B-hCG (less than 1000 mIU/mL) - Nephrotic syndrome (Gynecol Oncol 1995;59:300-3)

Macroscopic: - Mean size 5 cm - Fairly well-circumscribed; Infiltrative deep myometrial border - Sometimes polypoid - Sometimes hemorrhagic Placental Site Trophoblastic Tumour

Genetics: >85% have antecedent female gestation ROLE FOR PATERNAL X

Int J Gynecol Pathol 2008;27:562-67 Mod Pathol 2007;20:1055-60 Vs. Lab Invest 2000;80:965-72 55% XY

Exaggerated Placental Site Paternal contribution

45% XX

85% self limited; even with deep myometrial invasion

Behaviour: Predictors of poor outcome: - Extrauterine disease - Time from last pregnancy (>48 months) Lancet 2009;374:48-55 - Age > 35 years Gynecol Oncol 2006;100:511- 20 - Mitotic count > 5/10 hpf Gynecol Oncol 2001;82:415 - - Sheets of cells with clear cytoplasm 19 - B-hCG > 1000 Gynecol Oncol 1999;73:216 - - Diffuse p53 expression 22 Why Not Choriocarcinoma?

PSTT: CHORIOCARCINOMA:

B-hCG < 1000 B-hCG > 2500 p63 negative p63 positive Ki-67 up to 30% Ki-67 > 90% No syncytiotrophoblast Syncytiotrophoblast Distinct vascular colonization Basic Concepts in Placentation

FERTILIZATION IMPLANTATION NIDATION (pre-villous trophoblast) Choriocarcinoma: - Classical - “Monomorphic”/Atypical MESENCHYMAL VILLOUS FORMATION - Intraplacental (‘in situ’)

PRIMARY VILLI

CHORION FRONDOSOM “Chorangiocarcinoma” CHORION LAEVE (“placental disk”) Placental site nodule

IMPLANTATION OXYGENATION (“anchoring”) Legend: Non-neoplastic anatomic rests Exaggerated Placental Site Low grade malignant Placental site trophoblastic Malignant tumour Misunderstood kid CASE 3

37F

G1P1 (2 year old baby girl)

Vaginal bleeding and bulky uterus on ultrasound

Hysterectomy for “fibroids”

Pre-op hCG = 27 000

IHC INHIBIN HPL P63 Ki-67 What is your diagnosis? Epithelioid Trophoblastic Tumour

Macroscopic: - Discrete solitary nodule: - 50% Lower uterine segment/endocervix - 30% Fundus - 20% Extrauterine (ectopic, mets, etc)

Courtesy: Dr. R. Soslow ETT mimics: - HSIL - Invasive squamous cell carcinoma

Mod Pathol 2006;19:75- 82

Courtesy: Dr. R. Soslow Epithelioid Trophoblastic Tumour

Definition: Trophoblastic neoplasm showing differentiation toward chorionic-type intermediate trophoblast.

Clinical: - Women of reproductive age (mean 38 years) - Abnormal bleeding - Mean of 76 months post pregnancy - Low levels of B-hCG (less than 2500 mIU/mL)

Antecedent gestation: - Term gestation: 67% - Spontaneous abortion: 16% - Hydatidiform mole: 16%

Behaviour: - 75-85% are clinically benign - 15-25% metastasis Unfavourable histology: - 13% death Mitotic count > 6 per 10 hpf Gynecol Oncol 2015; 137:456-61 Int J Gynecol Cancer 2013;23:1334-38 J Obstet Gynecol 2011;204:11-18 Why Not Choriocarcinoma or PSTT?

PSTT: CHORIOCARCINOMA: ETT:

B-hCG < 1000 B-hCG > 2500 B-hCG < 2500 p63 negative p63 positive p63 positive Ki-67 up to 30% Ki-67 > 90% Ki-67 > 10% No syncytiotrophoblast Syncytiotrophoblast No syncytiotrophoblast Distinct vascular Distinct squamoid colonization appearance and calcifications

CHEMOTHERAPY

SURGERY Epithelioid Trophoblastic Tumour

How do you explain a beta-hCG of 27 000? But on the edge of one slide…

Ki-67 Mixed Epithelioid Trophoblastic Tumour and Choriocarcinoma Why Not Choriocarcinoma or PSTT?

PSTT: CHORIOCARCINOMA: ETT:

B-hCG < 1000 B-hCG > 2500 B-hCG < 2500 p63 negative p63 positive p63 positive Ki-67 up to 30% Ki-67 > 90% Ki-67 > 10% No syncytiotrophoblast Syncytiotrophoblast No syncytiotrophoblast Distinct vascular Distinct squamoid colonization appearance and calcifications

CHEMOTHERAPY

SURGERY CHORIOCARCINOMA METASTATIC TO BRAIN INVASIVE CANDIASIS AT AUTOPSY Take Home Message – No. 1 Lancet Oncol 2007;8:642-50 CYTOTROPHOBLAST Am J Surg Pathol 2007;31:1726-1732

VILLOUS INTERMEDIATE SYNCYTIOTROPHOBLAST TROPHOBLAST

(Extravillous) (Extravillous) Implantation site intermediate Chorionic intermediate trophoblast trophoblast - Exaggerated placental site - Placental site nodule NEOPLASTIC CYTOTROPHOBLAST STEM CELL

CHORIOCARCINOMA (arrest at nidation/pre-villous stage)

PLACENTAL SITE TROPHOBLASTIC TUMOUR EPITHELIOID TROPHOBLASTIC TUMOUR (maturation to implantation) (maturation to chorion) MIXED TUMOURS Take Home Message – No.2 (“Trophogram”) Ann Diagn Pathol 2007;11:228-34 TROPHOBLASTIC?

LMWCK (CAM 5.2) + INHIBIN +

B-hCG > 2500 B-hCG + syncytiotrophoblast CONFIRMED TROPHOBLASTIC

CHORIOCARCINOMA

p63 - p63 + hPL +++ hPL +/- CD146 + CD146 - IMPLANTATION TYPE CHORIONIC TYPE

Ki-67 < 1% Ki-67 > 10% Ki-67 < 8% Ki-67 > 12% CYCLIN E - CYCLIN E + EPS PSTT PSN ETT Developmental classification of GTD

FERTILIZATION IMPLANTATION NIDATION (pre-villous trophoblast) Choriocarcinoma: - Classical - “Monomorphic”/Atypical MESENCHYMAL VILLOUS FORMATION - Intraplacental (‘in situ’)

PRIMARY VILLI

CHORION FRONDOSOM “Chorangiocarcinoma” CHORION LAEVE (“placental disk”) Placental site nodule Epithelioid trophoblastic tumour

IMPLANTATION OXYGENATION (“anchoring”) Hydatidiform mole Legend: Non-neoplastic anatomic rests Exaggerated Placental - Complete Low grade malignant - Partial Site - Invasive / Metastatic Malignant Placental site Misunderstood kid trophoblastic tumour Placental malformations JACOB AT 3½ MONTHS

Early Complete Mole