Lymphoproliferative disorder of fetal origin presenting as oligohydramnios

Lymphoma involving the placenta or fetus remains a very rare event. All cas es reported to date have shown the lymphoma cells to be of maternal origin in that the tumor cells have preferentially involved the intervillous spare s with sparing of the villi and fetal circulation. We report a novel case o f a monoclonal primary placental Epstein-Barr virus (EBV)associated B-cell lymphoma of fetal origin. The placenta of a 20-week stillborn fetus born to a 19-year-old gravida 1 para 0 woman, presenting with oligohydramnios, sho wed a large cell infiltrate confined within villi and sparing the intervill ous spaces, indicative of preferential involvement of the fetal circulation . Necropsy did not show any other site of involvement by malignant lymphoma or other abnormalities. Immunophenotypic studies showed the tumor cells to be of B-cell phenotype with a relatively high proliferation rate. EBV EBER 1 RNA was identified in more than 95% of tumor cells, and polymerase chain reaction studies showed EBV EBNA1 strain type A and wildtype EBV LMP 1. Ana lysis of the immunoglobulin heavy chain by polymerase chain reaction showed a monoclonal B-cell population. In situ hybridization studies using a comm ercially available probe directed at repeated sequences on the human Y chro mosome showed a single intense signal within trophoblastic epithelium and l ymphoma cells, indicative of male origin. The mother remains in good health ii months after delivery.