Histiocytic Destruction of Red Blood Cells in the Bone Marrow: A Case-Based Approach

In this presentation, we will use a case-based approach to discuss the clinical finding, cytologic and histologic features, differential diagnoses, and pathogenesis of 3 histiocytic disorders involving bone marrow – 1. Precursor-targeted Immune Mediated Anemia (PIMA); 2. Hemophagocytic Lymphohistiocytosis (HLH); and 3. Hemophagocytic Histiocytic Sarcoma (HHS).  Considering that various features of these conditions are often overlapping, the distinction between them can be challenging.  A modified algorithm for approach to anemia will be used to help us in understanding where these reactive and neoplastic disorders fall in terms of their impact on hematopoiesis.  The veterinary literature as it relates to these disorders (PIMA, HLH, and HS references cited below) and mimics of these disorders also will be addressed. In this presentation, we will use a case-based approach to discuss the clinical finding, cytologic and histologic features, differential diagnoses, and pathogenesis of 3 histiocytic disorders involving bone marrow – 1. Precursor-targeted Immune Mediated Anemia (PIMA); 2. Hemophagocytic Lymphohistiocytosis (HLH); and 3. Hemophagocytic Histiocytic Sarcoma (HHS).  Considering that various features of these conditions are often overlapping, the distinction between them can be challenging.  A modified algorithm for approach to anemia will be used to help us in understanding where these reactive and neoplastic disorders fall in terms of their impact on hematopoiesis.  The veterinary literature as it relates to these disorders (PIMA, HLH, and HS references cited below) and mimics of these disorders also will be addressed.