Paraneoplastic tumefactive demyelination in a 47-year-old man with underlying seminoma

Tumefactive demyelination presents as an aggressive, fast progressive focal demyelinating lesion in the central nervous system, with often devastating clinical outcome if not acutely treated. Correct and early treatment is threatened by its real diagnostic challenge.

We describe a 47-year-old man with tumefactive demyelination and testicular seminoma. He presented with aphasia, cognitive impairment and right sided weakness of the arm and lower face. MRI revealed a lesion characteristic of tumefactive demyelination. Cerebral biopsy confirmed this diagnosis. In addition, a testicular seminoma was diagnosed. Temporal association of demyelination and malignancy was highly suggestive for a paraneoplastic syndrome. He responded well to corticosteroid therapy plus orchiectomy, but a behavioral disturbance remained.

A good knowledge of specific imaging characteristics of tumefactive demyelination can help in early diagnosis. Multiple underlying causes should be considered, including, but not limited to multiple sclerosis. A paraneoplastic syndrome should not be overlooked. This is the fifth case in which seminoma is associated with a paraneoplastic tumefactive demyelination lesion.