Neurological symptoms of familial hemophagocytic lymphohistiocytosis type 2

Hemophagocytic lymphohistiocytosis with central nervous system involvement is caused by inflammatory factor storms. The inflammatory factors invade the blood-brain barrier and further infiltrate brain tissue resulting in associated neurological and/or psychiatric symptoms in hemophagocytic lymphohistiocytosis with central nervous system involvement patients. This case report is based on a 14-year-old male patient who experienced intermittent dizziness and blurred vision about five years before admission as well as lower limb weakness and unstable walking approximately three years before admission. His brain MRI showed abnormal signals in the bilateral cerebellar hemisphere and vermis, right occipital lobe, and bilateral basal ganglia. The cerebrospinal fluid examination revealed an increase in nucleated cells, mainly monocytes, and elevated protein. He had no typical manifestation of hemophagocytic lymphohistiocytosis in the early stage, such as fever, cytopenia, or hepatosplenomegaly. He was misdiagnosed with meningoencephalitis or tuberculous meningitis. Perforin gene detection revealed a mutation in the PRF1 gene. The final diagnosis of type 2 familial hemophagocytic lymphohistiocytosis was made based on the neurological symptoms and genetic test. The possibility of hemophagocytic lymphohistiocytosis needs to be considered in patients with unexplained central nervous system symptoms, even if the patient does not have typical hemophagocytic lymphohistiocytosis symptoms, such as fever, cytopenia, or hepatosplenomegaly. We present the neurological symptoms of familial hemophagocytic lymphohistiocytosis type 2.