The myelin loss was near-total in the
cerebellum, except for relative sparing of the hilum and
fleece of the dentate nucleus, findings identical to those
described in Case 1 of Kornfeld et al (43) (Fig. 2C). In
Dr. Halliday’s case, cerebellar sections showed excellent
neuronal preservation in areas of severe myelin loss (Fig.
2D), numerous perivascular PAS-positive macrophages
containing coarse and even linear debris (Fig. 2E), and
trilaminar inclusions by EM (Fig. 2F). The severity of
Halliday’s case and Case 1 of Kornfeld et al (43) contrasts
sharply with the several-fold milder, ill-defined myelin
pallor and significantly fewer numbers of PAS-positive,
CD68-positive macrophages seen in our original
case (and in Case 2 of Kornfeld et al; Fig. 2G). Our
original case also manifested significant reactive astrocytosis,
even in areas with ostensibly intact myelin (Fig.
2H). Indeed, the signature pathological feature, and perhaps
the earliest morphological evidence of toluene leukoencephalopathy,
seems to be the presence of astrocytosis
and these perivascular PAS-positive macrophages
containing coarse or laminar myelin debris, which can be
found even in areas devoid of recognizable myelin damage
(Fig. 2H).