Escherichia coli Purulent Pericarditis and Pericardial Myeloid Sarcoma in Refractory Acute Myeloid Leukemia

Purulent pericarditis due to Escherichia coli is rare, typically occurring in immunocompromised hosts. We report a patient with acute myeloid leukemia presenting with recurrent E. coli bacteremia complicated by purulent pericarditis, with concurrent pericardial myeloid sarcoma and ecthyma gangrenosum-like cutaneous lesion. Microbiologic concordance of E. coli isolates from blood, pericardial fluid, and the skin lesion suggested hematogenous dissemination from a single source. The patient underwent surgical pericardial drainage and received intravenous antimicrobial therapy, resulting in microbiologic clearance and initial clinical improvement. However, the patient died five days after discharge in the setting of persistent profound neutropenia. This case illustrates that in patients with refractory hematologic malignancy and prolonged neutropenia, infection may persist or recur despite adequate source control and antimicrobial therapy, as durable control ultimately depends on recovery of host immune function. The case also highlights diagnostic challenges in pericardial disease, including discordance between cytologic analysis of pericardial fluid and histopathologic findings, and emphasizes the necessity of tissue biopsy in patients with acute myeloid leukemia presenting with pericardial effusion.​​