Case Presentation Brigitte M. Ronnett, MD Department of Pathology - PowerPoint PPT Presentation

Case Presentation Brigitte M. Ronnett, MD Department of Pathology The Johns Hopkins University School of Medicine Baltimore, MD USA

Case Presentation • The patient is a 39 year-old woman, G2P1, who presented with a missed abortion at 8-10 weeks and ultrasound findings suggesting a molar pregnancy (serum beta-HCG level not available). The material for review is from the curettage specimen.

Diagnosis? Original diagnosis: Partial hydatidiform mole • In follow-up, the beta-HCG level became undetectable by 6 months and remained so during an additional 6 months of follow-up, without requiring chemotherapy.

Case Presentation • Follow-up: 2 years later, 8 month history of dysfunctional uterine bleeding (menorrhagia), serum beta-HCG level 750,000 mIU/mL (patient reported that she had not been sexually active since the prior molar pregnancy) • Imaging studies & hysteroscopy: 6.0-7.8 cm uterine mass; no evidence of metastatic GTD • Curettage: markedly atypical trophoblast without villi

Algorithmic Approach to Diagnosis of Hydatidiform Moles Possible Hydatidiform Mole p57 Immunohistochemistry p57 negative p57 positive (villous stroma, cytotrophoblast) (villous stroma, cytotrophoblast) Molecular Genotyping Androgenetic Diploidy Diandric Triploidy Biparental Diploidy Complete Partial Non-molar Hydatidiform Mole Hydatidiform Mole

p57

p57

Non-molar Specimen: Biparental Diploidy p57 RNA p57 protein CH 3 p57 CH 3 p57: paternally imprinted, IHC CH 3 maternally expressed Positive in nuclei of villous stromal Maternal Chr 11 cells, cytotrophoblast, and intermediate trophoblast Paternal Chr 11

Partial Hydatidiform Mole: Diandric Triploidy p57 RNA p57 protein CH 3 CH 3 p57 p57 CH 3 p57: paternally imprinted, CH 3 IHC maternally expressed CH 3 CH 3 Positive in nuclei of villous Maternal Chr 11 stromal cells, cytotrophoblast, and intermediate trophoblast Paternal Chr 11 (2 copies)

Complete Hydatidiform Mole: Androgenetic Diploidy X X RNA p57 protein CH 3 CH 3 p57 p57 CH 3 p57: paternally imprinted, CH 3 IHC maternally expressed CH 3 CH 3 Negative in villous stromal cells and cytotrophoblast No maternal DNA (intermediate trophoblastic cells +) Paternal Chr 11 (2 copies)

Diagnosis? Original diagnosis: Partial hydatidiform mole Consultation diagnosis: • Androgenetic/biparental mosaic/chimeric conception with a molar component (complete hydatidiform mole)

Characterization of Androgenetic/Biparental Mosaic/Chimeric Conceptions, Including Those with a Molar Component Brigitte M. Ronnett, MD Department of Pathology The Johns Hopkins University School of Medicine Baltimore, MD USA

533 POC specimens analyzed by p57 IHC +/- genotyping 168 126 17 complex specimens 222 CHMs PHMs NMs per genotyping 11 specimens with distinct p57 and genotyping patterns 5 without foci 6 with foci of of trophoblastic trophoblastic hyperplasia hyperplasia

p57

FISH: diploid XX stromal cells & diploid XX cytotrophoblast

Non-molar mosaic specimen p57+ biparental diploid XX cytotrophoblast p57- androgenetic diploid XX villous stromal cells

p57+ biparental diploid cytotrophoblast & p57- androgenetic diploid villous stromal cells P:M = 2.5:1

Molecular Genotyping: Androgenetic/Biparental Diploid Mosaic Decidua VWA THO1 D13S317 179 183 217 221 186 P P Villi 183 171 P 209 M M M 179 186 221 3.1 P:M allele ratio 2.7 3.1

p57

p57

FISH: diploid XX stromal cells & diploid XX cytotrophoblast (both p57-discordant mosaic villi and p57-negative molar villi with trophoblastic hyperplasia)

Non-molar mosaic component p57+ biparental diploid XX cytotrophoblast p57- androgenetic diploid XX villous stromal cells

p57+ biparental diploid cytotrophoblast & p57- androgenetic diploid villous stromal cells P:M = 2.5:1

Molar component: features of CHM p57- androgenetic diploid cytotrophoblast p57- androgenetic diploid villous stromal cells

p57- androgenetic diploid cytotrophoblast & p57- androgenetic diploid villous stromal cells P:M = 2:0

p57

Non-molar mosaic p57+ biparental diploid XX cytotrophoblast p57- androgenetic diploid XX villous stromal cells component p57- androgenetic diploid XX cytotrophoblast Molar component: CHM p57- androgenetic diploid XX villous stromal cells

Mixture of p57+ & p57- biparental & androgenetic diploid cytotrophoblast & p57- androgenetic diploid villous stromal cells P:M ~ 5:1

Mosaic P:M = 2.5:1 component Molar component P:M = 2:0

Molecular Genotyping: Androgenetic/Biparental Diploid Mosaic with Molar Component Decidua Amelogenin THO1 TPOX CSF1PO 103 170 223 300 304 103 P Villi 175 P (no trophoblastic 239 P M hyperplasia) M 296 M 223 170 304 P:M allele ratio 5:1 3:1 4:1 P P P Villi 103 175 (with 239 296 trophoblastic hyperplasia) P:M allele ratio 2:0 2:0 2:0

p57

FISH: diploid XX stromal cells & mixed diploid XX, triploid XXX, and tetraploid XXXX cytotrophoblast (p57-discordant mosaic villi)

Non-molar mosaic component p57+ biparental diploid XX, triploid XXX, & tetraploid XXXX cytotrophoblast p57- androgenetic diploid XX villous stromal cells

p57+ biparental diploid, triploid, and tetraploid cytotrophoblast & p57- androgenetic diploid villous stromal cells P:M >2:1* *depends on number of paternal sets in aneuploid cells

p57

FISH: diploid XX stromal cells & diploid XX cytotrophoblast (p57-negative molar villi with trophoblastic hyperplasia)

Molar component: features of CHM p57- androgenetic diploid cytotrophoblast p57- androgenetic diploid villous stromal cells

p57- androgenetic diploid cytotrophoblast & p57- androgenetic diploid villous stromal cells P:M = 2:0

Molecular Genotyping: Androgenetic/Biparental Mosaic with Molar Component (CHM) Decidua THO1 D5S818 D3S1358 171 131 135 153 183 157 P P P Villi 123 175 148 (no trophoblastic Biparental M hyperplasia) M M (P:M > 2:1) 171 135 157 P:M allele ratio 2.7:1 4.3:1 3.9:1 P P P Villi 148 123 175 (with trophoblastic Androgenetic hyperplasia) P:M allele ratio 2:0 2:0 2:0

Molecular Genotyping: Androgenetic/Biparental Mosaic with Molar Component (CHM) Decidua THO1 D5S818 D3S1358 Amelogenin 103 131 135 171 183 153 157 Villi 103 P P P 175 148 123 (with trophoblastic hyperplasia) P:M allele ratio 2:0 2:0 2:0 Trophoblast 103 P P P 123 175 148 (recurrent GTD) M,M* M,M* 153, 157 131,135 M* M* *maternal DNA 171 183 contamination 2:0 P:M allele ratio 2:0 2:0

Case Presentation • Therapy: multi-agent chemotherapy (+high-risk factors); over 2 months, the beta-HCG levels declined significantly but plateaued (29 mIU/mL). • Hysterectomy: 5.0 cm firm yellow well-circumscribed mass in myometrium • Pathology: complete microscopic evaluation disclosed extensively necrotic tumor with surrounding inflammatory cells and only occasional multinucleated cells; immunohistochemical analysis demonstrated extensive expression of beta-HCG and focal expression of cytokeratins in the necrotic tumor • Follow-up: 4 weeks post-operatively, the serum beta-HCG level had declined to 3 mIU/mL; resumption of chemotherapy was planned for the post-operative period

Summary • Androgenetic/biparental mosaic/chimeric conceptions can be recognized by their unusual p57 expression patterns – Characterized by a mixture of p57-positive biparental and p57-negative androgenetic cells • Genotyping results are complicated, with variable paternal:maternal allele ratios and an excess of paternal alleles • Often misclassified as PHM by morphology • Those with a p57-negative androgenetic component with features of CHM have some risk of persistent GTD and warrant management as a molar pregnancy

Acknowledgements Johns Hopkins Molecular Diagnostics Laboratory: Cheryl DeScipio, PhD Lisa Haley, MS Katie Beierl, BS Stacey Mosier, BS ProPath, Dallas, TX: Kathleen M. Murphy, PhD Sharon Tandy, BS Debra S. Cohen, MS