Basophilic-Eosinophilic Meningitis in an Undifferentiated Myeloproliferative Disorder

BASOPHILIA and eosinophilia are common findings during an "accelerated phase" of chronic myeloproliferative disorders, particularly chronic myelogenous leukemia.1,2When these diseases involve the meninges, it is invariably as "leukemic meningitis," usually during the blastic transformation to acute leukemia, and blasts are the primary cell found in the CSF.3A case of an undifferentiated myeloproliferative disorder (Philadelphia chromosome negative) occurred, in which the terminal event was characterized by a severe infiltration of the meninges with basophils and, to a lesser extent, eosinophils, without the presence of leukemic blasts. Report of a Case A 40-year-old woman was seen at the hospital 2 1/2 years before her present admission with vaginal bleeding, leukocytosis (116,000/cu mm, with 1% blast forms, 2% myelocytes, 9% metamyelocytes, 34% band forms, 38% polymorphonuclear leukocytes, 3% lymphocytes, 2% monocytes, 1% basophils, and 2% eosinophils), thrombocytosis (3,500,000/cu mm), a normal bone marrow karyotype, a leukocyte alkaline phosphatase score