Progressive multifocal leukoencephalopathy. A case report with special reference to SV40 etiology

Area of Science:

• Neurology
• Virology
• Pathology

Background:

• Progressive multifocal leukoencephalopathy (PML) is a rare, demyelinating disease of the central nervous system.
• PML is typically caused by the JC virus (JCV), a polyomavirus.
• The role of other polyomaviruses, such as Simian virus 40 (SV40), in PML pathogenesis is less understood.

Observation:

• A 44-year-old female patient presented with progressive neurological deficits.
• Autopsy revealed extensive demyelination across the cerebrum, cerebellum, brain stem, and spinal cord.
• Intranuclear inclusion bodies and papova-like virions were identified in oligodendrocytes via electron microscopy.

Findings:

• Immunohistochemistry confirmed the presence of SV40 antigen within the intranuclear inclusion bodies.
• The extensive lesion distribution correlated with the duration of the patient's illness.
• The patient had a history of thyroid carcinoma, but no other significant immunosuppressive conditions.

Implications:

• This case suggests SV40 infection can cause PML with widespread demyelination.
• The prolonged clinical course may be linked to SV40 infection and potentially improved patient care.
• Further research is needed to elucidate the clinical significance and pathogenic mechanisms of SV40 in PML.