Hemophagocytic Histiocytosis Diagnosed by Fine Needle Aspiration Cytology of the Spleen

BACKGROUND: Hemophagocytic histiocytosis (HPS) is an idiopathic, familial or secondary syndrome characterized by mature histiocytes causing intensive erythrophagocytosis. CASE: A 2-month-old male suffering from autoimmune hemolytic anemia, fever, jaundice and hepatosplenomegalia underwent fine needle aspiration cytology of the spleen. Aspiration was performed using a 23-gauge, short needle with a subcostal approach. The smear showed a monomorphous cell population of mature histiocytes with marginal nuclei and wide, well-defined cytoplasm. The cytoplasm was microvaculated and often contained > or = 1 erythrocytes and occasional lymphocytes. Immunostaining performed on cytospin samples showed diffuse positivity for alpha-1-antichymotrypsin and S-100. Differential diagnosis with malignant histiocytosis, Langerhans histiocytosis and sinus histiocytosis with massive lymphadenopathy was established. HPS was diagnosed because of the cytologic and immunocytochemical features and clinical data. CONCLUSION: HPS may be diagnosed using fine needle aspiration of the spleen when other biopsy samples have been unsuccessful. Cytologic, diagnosis of HPS should always be considered in a specific clinical setting, because early treatment can often save the patient's life.