We reviewed clinical and pathologic characteristics of 18 cases of malignant histiocytosis including 2 autopsy cases with special interest on their immunohistochemical characteristics. We report 3 cases of unusual immunohistochemical finding and postulate these cases may be a supportive evidence of the view that dendritic cells share common precursor with those of mononuclear phagocytic system. More accumulated cases in the future and careful analysis would be needed to answer the basic question about the origin of malignant histiocytosis.
Adolescent ; Adult ; Antigens, Differentiation/analysis ; Biopsy ; Child ; Dendritic Cells/pathology ; Female ; Histiocytes/pathology ; Histiocytic Sarcoma/immunology/*pathology ; Humans ; Male ; Middle Aged ; Tumor Markers, Biological/analysis

OBJECTIVETo investigate the cell lineage and Epstein-Barr virus infection in previously diagnosed cases of malignant histiocytosis (MH) with tissue microarray technique.

METHODSUsing tissue-chips, immunohistochemical staining, in situ hybridization and PCR to analyze 5 autopsy cases of MH.

RESULTS(1) In all 5 cases, positive reactions of CD45RO, CD3 epsilon, TIA-1, Granzyme B were detected in the neoplastic cells, whereas negative reactions were found with CD30, CD20, CD56. (2) All cases revealed EBER1/2 positivity in neoplastic cells.

CONCLUSIONPreviously diagnosed malignant histiocytosis is an EBV-associated aggressive NK/T cell lymphoma.

Adolescent ; Adult ; Epstein-Barr Virus Infections ; pathology ; Female ; Histiocytic Sarcoma ; pathology ; virology ; Humans ; Immunohistochemistry ; In Situ Hybridization ; Lymphoma, T-Cell ; immunology ; Male ; Polymerase Chain Reaction