Transient focal lesion in the splenium of the corpus callosum: MR imaging with an attempt to clinical - physiopathological explanation and review of the literature Le lesioni focali transitorie dello splenio del corpo calloso: imaging RM ed ipotesi eziopatogenetiche

Purpose: To discuss the possible physiopathologic conditions responsible for these uncommon MR findings
on the basis of our experience and a review of literature.
Methods and Materials: In 6 patients, who underwent CT and MR examinations were incidentally detected
focal nonhemorrhagic lesions of the splenium of the corpus callosum. They were suspected for encephalitis (2),
dural sinus thrombosis(1), Multiple Sclerosis(3). MR examinations have been repeated after 4-8 and 12 weeks
and in two cases after 6 and 9 months also. MRI and medical records were reviewed retrospectively with respect
to the patients' clinical history, medication and laboratory findings to define the etiology of the lesions.
Results: In all patients the detected lesions revealed to be isolated, with no contrast enhancement and
reversible. In 4 patients the lesion disappeared after complete recovery of the underlying desease while in 2
patients the lesions persisted until to 6 and 9 months.
Conclusion: To our knowledge and according to other authors experiences, being these lesions detected in a
relatively wide number of conditions with heterogeneous etiopathogenetic factors, it leads to suppose a common
underlying physiopatologic mechanism, that considering signal characteristic, reversibility and white matter
location, could be represented by vasogenic edema.