Aim: To determine the degree of agreement between Ki67 and histopathology to differentiate between hydatidiform mole and hydropic abortus.

Methods: Descriptive, Cross Sectional Survey was conducted in the Department of Pathology, Fatima Memorial Hospital, Lahore during 6 months (May 11, 2016 to Nov 11, 2016). Using non-probability consecutive sampling, 105 cases were included in this study as per the inclusion and exclusion criteria. 10% buffered formalin was used to fix the sepecimens. Gross examination and staining with Hematoxylin and Eosin was done. The cases were diagnosed by a histopathologist. IHC staining Ki67 was performed, assessed by histopathologist and the data was recorded on the proforma.

Results: The mean age was 27.79±5.81 years with minimum and maximum ages of 18 years and 42 years respectively. The histopathological findings showed hydatidiform mole in 41 (39%) women and hydropic abortus in 64(61%) women. The Ki67 was reported to be >25 in 41(39%) patients and less than or equal to 25 in 64(61%) patients. The agreement of differentiation in the two types for histopathology and Ki67 was found in 101(96.2%) patients. Kappa statistics showed 92% (p-value= 0.000) strength of agreement between histopathology and Ki67.

Conclusion: There is high degree of agreement between Ki67 and histopathology for differentiation of hydatidiform mole and hydropic abortus. So Ki67 can be used as an adjacent in histopathologic diagnosis of hydatidiform mole in difficult cases.

MeSh words: Hydatidiform Mole, Immunohistochemistry, Ki-67 Antigen