Hemophagocytic histiocytosis: A Clinicopathological correlation

Objectives: Histiocytic hyperplasia with hemophagcytosis (HP) is relatively uncommon condition that has often been mistaken in the past for neoplastic disorders. This study was undertaken to investigate the possible etiology of HP, its intensity in the bone marrow and also its effect on hematological parameters with the extent of disease activity. Methods: Blood samples were collected and bone marrow examination was performed in 250 patients with varied etiology showing HP. Complete bloodcounts, reticulocyte count, and RBC morphology were determined. HP was examined in the bone marrow smears by leishman staining. Severity of HP was determined by grading of its intensity in the bone marrow smears. Results: Our data showed variable degree of HP (mild, moderate, severe) in the bone marrow smears of patients having different underlying disorders. Hemophagorytic syndrome (HPS) with clinical and biochemical derangements was found in 24 (9.6%) patients. HPS was mostly associated with infection. The etiological distribution in different group of disorders was ;nonmalignant-hematological-conditions (NMHC) (56.80%), infections (24.80%), storage disorders (4.40%), malignant hematological conditions (4.40%) autoimmune disorders (1.20%) and miscellaneous group (8.40%). Distribution of patients in different grades of intensity of HP was ;grade I (35.50%; mild), grade II (45.50%; moderate) and grade III (19.60%; severe). Conclusion: We conclude that severe degree of HP has profound effect on hematological parameters particularly hemoglobin and platelet counts. This phenomenon may presents as HPS with fatal outcome. We also conclude that there was no effect of age on either intensity of HP or on blood counts.