A teenage boy with late onset hemophagocytic lymphohistiocytosis with predominant neurologic disease and perforin deficiency

Familial hemophagocytic lymphohistiocytosis (FHLH) is an autosomal recessive disorder of cytotoxic cell function that results in abnormal proliferation of benign lymphocytes and histiocytes in response to infectious stimuli. FHLH generally occurs in very young children, and typically presents with fever, cytopenias, coagulopathy, lymphadenopathy, and hepatosplenomegaly. Central nervous system involvement occurs frequently and may precede the development of systemic symptoms by months to years. We report a case of an 18-year-old male with a 2-year history of symptoms attributed to a demyelinating disorder, who succumbed to rapidly progressive hemophagocyte lymphohistiocytosis. Post-mortem, two distinct perforin mutations were identified. We discuss the central nervous system and genetic findings in this unusual presentation of familial hemophagocytic lymphohistiocytosis.