[Proton MRS in a case of intracerebellar epidermoid]

We report a case of epidermoid, in which proton MR spectroscopy(MRS) provided additional information to MRI. The tumor revealed high signal intensity on T2-weighted images(WI) and low signal intensity on T1 WI. No enhancement was observed. Proton MRS was acquired with the Proton Regional Imaging of Metabolites(PRIME) method(TR/TE/measurements = 2,000 ms/136,272 ms/128 times). Proton MRS revealed lactate(Lac) peak at 1.33 ppm as negative peak at TE 136 ms and positive peak at TE 272 ms. N-acetylaspartate(NAA), creatine/phosphocreatine(Cr) and choline-containing compounds(Cho) were not visible. Lac peak without other peaks such as NAA, Cr, Cho is a unique finding of proton MRS for epidermoid and this could be useful in the differential diagnosis.