Circulating Megakaryocytes in a Peripheral Blood Smear at the Feathered Edge: An Incidental Finding in a Case of Systemic Inflammatory Response Syndrome

Megakaryocytes are large cells with lobulated nuclei found within the bone marrow and comprising 0.01% of all nucleated cells. Circulating megakaryocytes in the peripheral blood smear (PBS) have been rarely described in the literature. We here report a case of a 41-year-old female presented with generalized weakness, high-grade fever (100.8°F), and nausea. Hematology laboratory reports showed anemia and leukocytosis (18.9 × 10 3 /L) with a predominance of neutrophils (95%) and mature megakaryocytes in her PBS at the feathered edge. The laboratory findings of clinical chemistry revealed elevated urea, creatinine, and deranged liver function. This case highlights the rare occurrence of megakaryocytes in the PB of a patient suffering from systemic inflammatory response syndrome. The primary objective of the case study is to gain a better understanding of megakaryocyte biology and its role in the pathogenesis of systemic inflammatory responses.