Blast-like cells in cerebrospinal fluid of neonates. Possible germinal matrix origin.

Primitive cell clusters (PCCs) composed of immature blast-like cells were observed in Wright's-stained cerebrospinal fluid (CSF) cytocentrifuge specimens from four infants over an 18-month period. All of these patients had hydrocephalus; in three this was secondary to subependymal germinal matrix intraventricular hemorrhage (IVH) associated with prematurity. The fourth was associated with Arnold-Chiari malformation, Chiari type II. In the CSF samples from the patients with IVH, hemosiderin-laden macrophages were also prominent and, in some cases, were intimately admixed with the PCCs. Immunoperoxidase staining of cytocentrifuge preparations from one of the patients revealed that the PCCs stained with neuron-specific enolase (NSE) but not with pan-leukocyte antibodies. Cells with similar morphologic characteristics to PCCs in the CSF of infants have been infrequently illustrated in the literature and thought to be of hematopoietic origin. However, the immunohistochemical findings and the clinical presentation suggest that PCCs are most likely germinal matrix cells.