Malakoplakia of the brain. A report of two cases occurring in childhood.

Malakoplakia was found in the brain biopsy specimens of two children with meningoencephalitis probably due to herpes simplex. Histologically, there was extensive parenchymal destruction and cellular infiltration. Numerous von Hansemann histiocytes and typical Michaelis-Gutmann bodies were present. Ultrastructurally these bodies had a dense central core and concentric alternating rings. Large intracytoplasmic phagolysosomes were present. Malakoplakia most frequently involves the urinary tract of adults. Only a few children with malakoplakia have been described. There are two previous reports of cerebral malakoplakia associated with neonatal herpes simplex. The pathogenesis is obscure. Several reports suggest an altered histiocytic response to a bacterial agent as the pathogenetic mechanism. Our findings raise the possibility of an etiologic role of a virus, such as herpes simplex.