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Isolated central nervous system hemophagocytic lymphohistiocytosis: case report.

OBJECTIVE AND IMPORTANCE
The first case of histologically proven hemophagocytic lymphohistiocytosis (HLH) isolated to the central nervous system (CNS) is reported. HLH affecting the CNS mimics several neurological disorders and may be misdiagnosed. The diagnostic and therapeutic problems of this disease are discussed.


CLINICAL PRESENTATION
We report a case of a 5-year-old girl with a 2-month history of right hemiparesis. The initial magnetic resonance imaging scan mimicked the appearance of malignant glioma or cerebral infarction. By use of neuroimaging alone, it was extremely difficult to reach an appropriate diagnosis.


INTERVENTION
Pathological examination of a surgical specimen of the lesion revealed histological characteristics typical of HLH. Because of the absence of both physical and blood chemical findings of systemic HLH, the patient was diagnosed as having HLH isolated in the CNS without systemic HLH. Radiotherapy with corticosteroid administration led to complete resolution of the CNS lesions, but the duration of remission was only 3 months. The patient died secondary to refractory progression of the CNS lesion.


CONCLUSION
Radiotherapy with corticosteroid administration led to a complete resolution of the lesions, although for only a transitory remission. Although HLH is extremely rare, the existence of this disease isolated in the CNS should be documented, and further case accumulation and therapeutic investigations are needed to clarify the pathophysiological characteristics of this disease.