Thymoma associated paraneoplastic encephalitis (TAPE), a potential cause of limbic encephalitis

Area of Science:

• Neurology
• Oncology
• Immunology

Background:

• Autoimmune encephalitis presents with diverse neurological symptoms.
• Paraneoplastic syndromes can arise secondary to an underlying malignancy.
• Thymoma is a rare tumor associated with various paraneoplastic phenomena.

Observation:

• A 59-year-old man presented with expressive aphasia and memory deficits, progressing to seizures.
• Initial investigations suggested herpes simplex virus (HSV) encephalitis, but HSV PCR was negative.
• Brain MRI revealed findings suggestive of HSV encephalitis.

Findings:

• Further testing identified autoimmune encephalitis linked to an incidental thymoma.
• The patient's presentation and response to treatment indicated thymoma-associated paraneoplastic encephalitis.
• This condition requires differentiation from infectious etiologies like HSV encephalitis.

Implications:

• Early recognition and prompt immunotherapy are vital for managing paraneoplastic encephalitis.
• Cancer-directed therapy, including thymoma resection, improves neurological recovery and reduces relapse risk.
• Delayed treatment can lead to progressive neurological deterioration and mortality.