B-cell-type malignant lymphoma with placental involvement.

We present here a case of B-cell-type mediastinal malignant lymphoma during pregnancy complicated by placental involvement. In this case, some nodular high-echo patterns were recognized in the placenta by ultrasonography. A cesarean section and resection of the mediastinal tumor were performed at 33 weeks and 6 days of gestation due to the deterioration of the dyspnea. A female infant weighing 1,868 g was delivered and she is now a healthy 2-year-old. The mother, however, died of the disease 1 month after surgery, due to progression of the tumor. The placenta showed numerous white firm nodules varying from 3 mm to 3 cm in diameter. The pathologic findings of both the mediastinal tumor and the placenta indicated primary mediastinal (thymic) B-cell lymphoma.