The Great Mimicry: Platelet Artefacts Masquerading as Trypanosomes

Abstract

Introduction: Peripheral smear evaluation is essential in hematologic diagnosis, but EDTA-induced and storage-related artefacts can mimic infections, malignancies, or thrombocytopenia by altering blood cell morphology. Recognizing these artefacts is crucial to avoid misdiagnosis, and a fresh fingerprick smear may be necessary for accurate assessment. Case Presentation: We report an uncommon case of artefactual platelet morphology mimicking flagellated hemoparasites on peripheral smear in a 45-year-old male with chronic kidney disease stage V on dialysis, who presented with headache, nausea, and severe hypertension (BP 260/160 mmHg). His hemogram revealed anemia (Hb 5 g/dL), leukopenia (3.9 × 10⁹/L), and a normal platelet count (1.02 × 10⁵/µL), with no history of fever or blood loss, and renal function was markedly deranged (serum creatinine 6.40 mg/dL). A Leishman-stained smear from an early morning EDTA sample showed burr cells and numerous extracellular, slender, eosinophilic, tapered structures (~5–6 µm), resembling miniature trypanosomes but lacking kinetoplasts, consistent with artefactually elongated platelets. Discussion: Elongated or flagellated platelet forms may result from mechanical artefacts during smear preparation, potentially mimicking hemoparasites and leading to diagnostic confusion. This case highlights the importance of clinical correlation and confirms that a properly prepared fingerprick smear is a reliable tool for distinguishing artefactual changes from true pathology. Conclusion: Pathologists should be alert to artefacts that mimic parasites or abnormal cells, especially in suspected thrombocytopenia or infection. In doubtful cases, a fresh fingerprick smear offers more reliable assessment of platelet morphology.