True histiocytic malignancy associated with a malignant teratoma in a patient with 46XY gonadal dysgenesis

The relatively frequent association of hematologic neoplasia and primary mediastinal germ cell tumors has been reported. Of these hematologic malignancies, nine were classified as malignant histiocytosis or acute monoblastic leukemia, and all occurred in males. We now report on a patient who was phenotypically female, with 46XY gonadal dysgenesis, and who developed a true histiocytic malignancy that presented as a large hepatic tumor and also involved the spleen, right kidney, and lymph nodes. Twenty-six months before the development of the histiocytic malignancy, an ovarian malignant teratoma with yolk sac elements was removed; the patient subsequently received chemotherapy. The neoplasm was composed of large pleomorphic cells and the histiocytic nature was established by cytologic, cytochemical, immunologic, and ultrastructural studies. In the course of her illness, the patient developed classic acute monoblastic leukemia 8 months after the diagnosis of histiocytic malignancy. Karyotypic analysis of the hepatic tumor, bone marrow, and blood showed 46XY gonadal dysgenesis. We believe that this is the first reported case of a phenotypically female patient who developed these two rare malignancies. It suggests that the association between germ cell tumors and histiocytic malignancy in genotypically male individuals may not be coincidental or secondary to therapy, but may be a phenomenon related to dysgenetic gonads in the presence of a Y chromosome.