The "dark cerebellar sign".

We present and discuss the "dark cerebellar sign" in contrast to the well known "white cerebellar sign". The "white cerebellar sign" relates to a normal cerebellum which appears hyperdense in contrast to a pathological hypodense cerebrum on computer tomography (CT). We present a child with a "dark cerebellar sign" characterized by an ischemic or edematous cerebellum which appears hypodense in contrast to a normal relatively dense cerebrum. Isolated infarction of the cerebellum is a rare finding in premature neonates. Even rarer, cerebellar infarction may be observed in children and young adults due to an overdose of tricyclic antidepressants (TCA). The reason for the selective cerebellar infarction with TCA intoxication is still unknown. Our case shows that TCA intoxication should be included in the differential diagnosis of children with a "dark cerebellar sign".