Extensive Platelet Phagocytosis in a Patient with Immune Thrombocytopenia (ITP) and Concomitant Tuberculosis

Excerpt

Hemophagocytic syndrome is characterized by benign proliferation of mature histiocytes and uncontrolled phagocytosis of the erythrocytes, leukocytes, platelets and/or their hematopoietic precursors in the bone marrow. Hemophagocytic syndrome can be familial or acquired which is associated with tuberculosis, autoimmune disorders, hematologic malignancies or solid cancers [1]. Although histiocytes in the bone marrow may show phagocytosis of any of the hematopoietic precursors, marked platelet specific phagocytosis is an extremely rare finding. Inhibitory CD47/(signal regulatory protein) SIRP alpha signaling is involved in regulating platelet phagocytosis in ITP [2]. We present a patient with ITP who had concomitant tuberculosis and showed predominant platelet phagocytosis. A 61 years old male with ITP on steroid therapy presented with fever and cough since 2 weeks. He had pallor with no petechiae or purpuric spots. Investigations showed hemoglobin of 102 g/l with normal white cell count and thrombocytopenia (platelets: 58 × 10⁹/l). Bone marrow aspiration showed increase in histiocytes with many of them showing extensive platelet phagocytosis (Fig. 1). Occasional histiocytes also showed erythroblastic phagocytosis (Fig. 1, Inset). Trephine biopsy and clot section showed epithelioid cell granulomata (Fig. 2a, b). Ziehl–Neelsen stain for acid fast bacilli was positive. HRCT chest was suggestive of military tuberculosis. The patient was started on anti-tubercular treatment and was discharged in a stable condition.

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