Bone marrow hypoplasia in eight dogs with Sertoli cell tumor.

Eight male dogs with Sertoli cell tumor had pancytopenia and bone marrow hypoplasia attributed to endogenous estrogen myelotoxicosis. Clinical signs were hemorrhage caused by thrombocytopenia, anemia caused by blood loss or diminished erythrocyte production, and infection and fever associated with granulocytopenia. Other signs attributed to hyperestrogenism were feminization and prostatic disease. Two dogs recovered after castration and supportive treatment, but 5 other similarly treated dogs died of hematopoietic failure. One dog was euthanatized.