title: Diandric triploid hydatidiform mole with loss of maternal chromosome 11.
abstract: Distinction of hydatidiform moles (HM) from nonmolar specimens and their subclassification as complete (CHM) versus partial hydatidiform mole (PHM) are important for clinical practice and investigational studies to refine ascertainment of risk of persistent gestational trophoblastic disease (GTD), which differs among these entities. Immunohistochemical analysis of p57 expression, a paternally imprinted maternally expressed gene on 11p15.5, and molecular genotyping are useful for improving diagnosis. CHMs are characterized by androgenetic diploidy, with loss of p57 expression due to lack of maternal DNA. Loss of p57 expression distinguishes CHMs from both PHMs (diandric triploidy) and nonmolar specimens (biparental diploidy), which retain expression. We report a unique HM characterized by morphologic features suggesting an early CHM, including lack of p57 expression by immunohistochemistry, but with genetic features more in keeping with a PHM. Specifically, molecular genotyping by short tandem repeat markers provided evidence to support interpretation as a PHM by demonstrating allele patterns and ratios most consistent with diandric triploidy, with evidence of loss of the maternal copy of chromosome 11 to explain the lack of p57 expression. This case illustrates the value of combined traditional pathologic and ancillary molecular techniques for refined diagnosis of molar specimens. It also raises questions regarding which modalities should be used to ultimately define the subtypes of HMs and whether chromosomal losses or gains, particularly involving imprinted genes such as p57, might play a role in modifying risk of persistent GTD.
authors: Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, MD, USA. cheryldescipio@jhmi.edu
authors: Cheryl
authors: C
authors: DeScipio
authors: Lisa
authors: L
authors: Haley
authors: Katie
authors: K
authors: Beierl
authors: Ashwini P
authors: AP
authors: Pandit
authors: Kathleen M
authors: KM
authors: Murphy
authors: Brigitte M
authors: BM
authors: Ronnett
mesh_terms: D000328:Adult; D002872:Chromosome Deletion; D002880:Chromosomes, Human, Pair 11; D050761:Cyclin-Dependent Kinase Inhibitor p57 / Q000172:deficiency; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006828:Hydatidiform Mole / Q000145:classification / Q000175:diagnosis* / Q000235:genetics; D010388:Pelvis / Q000000981:diagnostic imaging; D011247:Pregnancy; D057885:Triploidy; D014463:Ultrasonography; D014594:Uterine Neoplasms / Q000175:diagnosis* / Q000235:genetics
chemical_list: C493964:CDKN1C protein, human; D050761:Cyclin-Dependent Kinase Inhibitor p57