Cranial MR and proton MR spectroscopy findings in hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a nonmalignant disorder of immune regulation, with overproduction of cytokines and diminished immune surveillance. Symptoms are nonspecific and may affect multiple organs, including the central nervous system (CNS). Seizures, focal neurologic deficits, and gait abnormalities are the most common neurologic manifestations. Neuroimaging findings have been described in case reports and small series; however, magnetic resonance spectroscopy (MRS) findings have not been described extensively. We report a 19-month-old boy with HLH with CNS involvement. Brain MR imaging basically revealed non-specific confluent white-matter involvement. On MRS major metabolite ratios were found as: NAA(N-acetylaspartate)/Cho(choline) 1.85, NAA/Cre(creatine) 2.40, and Cho/Cre 1.29, which did not statistically differ from the control group (p>0.05). This presence of lactate indicates that the normal cellular oxidative respiration is no longer in effect, and that carbohydrate catabolism is taking place. MRS findings has been reported in one case before. Herein, we report the abnormal lactate peak that have been shown for the first time with MRS in HLH.