title: The Diagnosis of Choriocarcinoma in Molar Pregnancies: A Revised Approach in Clinical Testing.
abstract: BACKGROUND
  Hydatidiform moles occur in approximately 1 in 1,500 pregnancies; however, early miscarriages or spontaneous abortions may not be correctly identified as molar pregnancies due to poor differentiation of chorionic villi.
  
  
  METHODS
  The current clinical testing algorithm used for the detection of hydatidiform moles uses a combination of morphological analysis and p57 immunostaining followed by ploidy testing to establish a diagnosis of either a complete or partial molar pregnancy. We review here 198 referrals for fluorescence in situ hybridization (FISH) ploidy testing, where the initial diagnosis based on morphology is compared to the final diagnosis based on a combination of morphology, FISH and p57 immunohistochemical (IHC) staining.
  
  
  RESULTS
  Approximately 40% of cases were determined to be genetically abnormal, but only 28.8% of cases were diagnosed as molar pregnancies. The underestimation of complete molar pregnancies and those with androgenetic inheritance was also found to be likely using conventional diagnostic methods, as atypical p57 staining was observed in approximately 10% of cases.
  
  
  CONCLUSIONS
  Our findings suggest that a revised approach to testing products of conception is necessary, with cases screened according to their clinical history in order to distinguish molar pregnancy referrals from hydropic pregnancies.
authors.affiliation: Diagnostic Genetics, LabPLUS, Auckland City Hospital, Auckland, New Zealand.
authors.forename: Lisa
authors.initials: L
authors.lastname: Duffy
authors.affiliation: Diagnostic Genetics, LabPLUS, Auckland City Hospital, Auckland, New Zealand.
authors.forename: Liangtao
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Diagnostic Genetics, LabPLUS, Auckland City Hospital, Auckland, New Zealand.
authors.forename: Karen
authors.initials: K
authors.lastname: Sheath
authors.affiliation: Diagnostic Genetics, LabPLUS, Auckland City Hospital, Auckland, New Zealand.
authors.forename: Donald R
authors.initials: DR
authors.lastname: Love
authors.affiliation: Diagnostic Genetics, LabPLUS, Auckland City Hospital, Auckland, New Zealand.
authors.forename: Alice M
authors.initials: AM
authors.lastname: George
keywords: Fluorescence in situ hybridization; Hydatidiform moles; Molar pregnancies; Ploidy