NCIt definition : A classification of rare, non-neoplastic, proliferative disorders of the hematologic
system. Primary or familial hemophagocytic lymphohistiocytosis (HLH) is inherited
with an autosomal recessive pattern with five known subtypes differentiated by specific
genetic mutations. Secondary manifestation of HLH is usually seen in hyperactivated
immunologic states such as infection, autoimmune disease or malignancy. Histiocytes
in the bone marrow, spleen or lymph nodes become activated to the point that phagocytosis
proceeds unchecked. Clinical signs usually present within the first decade and include
fever, jaundice, hepatosplenomegaly, lymphadenopathy and skin rash. Prompt initiation
of treatment improves survival though prognosis remains poor even with intervention.;
NCIt note : See 'Familial Hemophagocytic Lymphohistiocytosis(C61276)';