The diagnosis in this case was tumefactive demyelination, which may be thought of as a solitary demyelinating lesion measuring greater than 2 cm and with characteristics that mimic neoplasm.

本例的诊断是肿瘤样脱髓鞘病变，这被认为是一种孤立的脱髓鞘病变，大小超过2cm，其特征类似于肿瘤样病变。