Platelet aggregation with various morphologies of neutrophils in arterial thrombus in a patient with Coronavirus disease: a case report.

Arterial thromboembolism is a life-threatening condition in COVID-19 patients; however, the mechanism of hypercoagulopathy remains unknown. A 62-year-old man with a history of obesity was diagnosed with COVID-19 pneumonia. After hospitalisation, unfractionated heparin was administered because of increased D-dimer levels; nevertheless, an arterial embolism in the left lower limb developed on the following day. Enhanced computed tomography revealed an occluded left iliac artery and intra-aortic thrombus at the juxtarenal level. Urgent thrombectomy was performed. On post-operative day 6, coumadin was initiated to treat the remaining thrombus. The patient was discharged without any complications. The removed thrombus pathologically presented platelet aggregation and degenerated neutrophils that were in various time axes; some neutrophils had clear margins of nuclear membrane, whereas others had pyknotic and fragment nuclei. We believe that the platelet formation and the neutrophils in several time axes could be key factors in promoting thrombus formation in COVID-19 patients.