Hemophagocytosis simulating malignant histiocytosis: a terminal event of the myelodysplastic syndrome

Myelodysplastic syndrome (MDS) as a late stage of subclinical hemophagocytic lymphohistiocytosis (HLH): a putative role for Leptospira infection. A hypothesis

It is proposed that hemophagocytic lymphohistiocytosis (HLH) and myelodysplastic syndromes (MDS) may be temporally distinct phases of pathophysiologically related disease processes. A significant subgroup of MDS may develop from subclinical HLH. In that case, HLH-like disease would chronically proceed with little disease activity or under occasional flares only, until it first becomes clinically apparent at the MDS stage. At the MDS stage, however, HLH activity may be easily overlooked by histological or cytogenetic means, since hemophagocytosis has fallen already largely silent. Current treatment options for HLH, like high-dose intravenous immunoglobulins (IVIG), may turn out to be helpful in MDS patients as well. In rare and extreme cases, Leptospira infection causes severe and life-threatening HLH. Thus, this proposal also implies that an insufficient, dysfunctional or misdirected immunological response to Leptospira infection may lead to MDS in the long run in a significant number of cases, which have not been recognized as Leptospira -triggered events in the first place. Infections by agents other than Leptospira may lead to subclinical HLH-like disease with MDS as a late stage as well.

Hemophagocytic syndrome associated with hematological neoplasias

Hemophagocytic syndrome (HPS) is a reactive process that complicates several diseases including hematological neoplasias (HN). It has been suggested that HPS may be a negative prognosis factor for neoplastic diseases. In this retrospective analysis, 13 cases with HPS associated to HN were compared with two age, sex, diagnosis, disease stage and treatment matched controls in order to determine the impact of this syndrome on the survival. Cases with HPS were adult patients with a male:female ratio of 1:1 and their clinical picture was characterized by fever, lymphadenopathy, hepatosplenomegaly, and pancytopenia. Median survival since HN diagnosis was 7 and 48 months for the HPS and control groups, respectively (P = 0.0001). In ten patients who died, median survival after HPS presentation was 1 month. These results suggest that the presence of HPS is a negative prognosis factor in patients with HN. Due to its high mortality rate, an individualized, early, and intensive chemotherapeutic regimen may be required for HN complicated with this syndrome.

Hemophagocytosis by small cell lung carcinoma

A 60-year-old woman with disseminated small cell carcinoma of the lung and hemophagocytosis by the metastatic cells in the bone marrow is presented. It is the first clinicopathologic report on phagocytosis of erythrocytes by lung tumor cells in concordance with a recently described evidence of a macrophage origin of small cell carcinoma of the lung.