Published online Nov 16, 2015. doi: 10.12998/wjcc.v3.i11.956
Peer-review started: April 18, 2015
First decision: May 13, 2015
Revised: June 30, 2015
Accepted: August 4, 2015
Article in press: August 7, 2015
Published online: November 16, 2015
Core tip: A vanishing brain space occupying lesion is defined as reduction or disappearance of a brain lesion spontaneously or after steroid treatment to ≤ 70% of its size before establishing its definitive diagnosis. A vanishing solitary neoplastic/non-neoplastic (pseudotumor) (e.g., infection/abscess, granuloma, radiation necrosis, multiple sclerosis) brain mass in a child poses a considerable diagnostic difficulty particularly deeply seated lesions in which tissue diagnosis is difficult to be done. In clinical practice, neuroimaging has to be done every 6-12 mo for at least 3-5 years to follow up after complete remission of the patient. Magnetic resonance spectroscopy (MRS) has been proved to be valuable for diagnostic differentiation between tumor and pseudotumor lesions. MRS provides information related to the metabolic activity in the culprit lesion (e.g., neoplastic processes, demyelination, cell necrosis or gliotic changes).