ASYMPTOMATIC PONTINE LESIONS FOUND BY MAGNETIC-RESONANCE-IMAGING - ARE THEY CENTRAL PONTINE MYELINOLYSIS

Clinicians occasionally receive radiographic reports noting pontine le sions in their patients who have undergone magnetic resonance imaging (MRI) for symptoms not referable to the pens. Based on these relativel y isolated lesions, patients may receive the presumptive radiographic diagnosis of central pontine myelinolysis (CPM). Review of our MRI dat abase from the last five years identified twelve such patients with hy perintense pontine lesions on T2-weighted scans which were out of prop ortion to supratentorial white matter disease processes and unexplaine d by the remainder of their radiographic studies. In an attempt to fur ther clarify whether these findings were more consistent with CPM or s ome other process, we reviewed these patients' clinical records with p articular attention to electrolyte disturbances, alcoholism, liver dis ease and hypertension. We also compared the MRI studies from these twe lve patients with four MRI scans from patients with clinically diagnos ed CPM and with eight post-mortem MRI scans on autopsy-proven asymptom atic CPM. By comparing pre- and post-mortem scans, five of the twelve unknown pontine lesions were felt to be too large to represent asympto matic CPM. Five were thought to be incompatible with CPM based on shap e and/or discohesiveness; one of these came to autopsy and showed cere bral and pontine ischemic rarefaction, not CPM. Only two of these twel ve cases were felt to be asymptomatic or mildly symptomatic CPM, but h ave not come to autopsy. We conclude that pontine lesions found incide ntally on MRI scans are a heterogeneous group, many of which are more consistent with pontine ischemic rarefaction than with asymptomatic CP M. (C) 1997 Elsevier Science B.V.