Mycoplasmal cerebral vasculopathy in a lymphoma patient: Presumptive evidence of Mycoplasma pneumoniae microvascular endothelial cell invasion in a brain biopsy

A 73-year-old man had episodic encephalopathy, ataxia and neuropathy. Symptoms largely resolved but adenopathy later lead to the diagnosis of a low-grade follicular lymphoma. The neurological symptoms soon recurred with new pontine calcifications identified by computed tomography. Brain biopsy revealed microvascular endothelial cell nuclear changes. Electron microscopy identified small polymorphic bacteria without a cell wall and with terminal and attachment organelles within endothelial cells and clustered in some microvascular lumina. Immunostaining was positive for Mycoplasma pneumoniae and convalescent serum enzyme immunoassay was positive for M. pneumoniae IgG. The patient again recovered and he was neurologically stable 33 months after the initial episode. The ultrastructural findings of the bacterial cells are distinctive of some mycoplasmal species when compared to other small bacteria. Mycoplasma-like organisms are reported in four autopsied patients who had chronic encephalopathy, movement disorders, and some of the same light- and electron-microscopic findings in the brain as our patient. Direct neuroinvasion by Mycoplasma species has been suggested, while anatomic observations in our patient and in the four autopsy cases show microvascular invasion but not parenchymal invasion. Most mycoplasmal encephalitis may be immune-mediated. The frequency of neurovascular invasion is not known. It may be rare and it may persist.