Baló's concentric sclerosis and tumefactive demyelination: a shared immunopathogenesis?

Baló's concentric sclerosis (BCS) and tumefactive demyelination (TD) are considered atypical forms of multiple sclerosis (MS). Baló lesions are characterized by concentric rings corresponding to alternating bands of demyelination and relatively preserved myelin (Hu and Lucchinetti, 2009). Tumefactive lesions are pseudotumoural demyelinating lesions of >2 cm and may have an open ring-enhancing magnetic resonance imaging appearance (Hu and Lucchinetti, 2009; Lucchinetti et al., 2008; Altintas et al., 2012). We present a patient who developed limb weakness and focal seizures secondary to a lesion radiologically and histopathologically consistent with BCS who, six months later, developed a tumefactive demyelinating lesion. This is the first description of BCS and TD occurring in the same patient and is particularly notable because of the lack of any other more typical demyelinating lesions on the MRIs. The nature of BCS and TD in relation to more typical multiple sclerosis is discussed.