Isolated Myeloid Sarcoma Masquerading as Scattered Abscesses in a Septic Patient: A Case Report and Literature Review.

Introduction: Myeloid sarcoma (MS) is also known as chloroma, extramedullary acute myeloid leukemia (AML), or granulocytic sarcoma. MS is a rare extramedullary infiltration of myeloid cells, most commonly collecting in the skin and causing a small number of localized lesions. It is strongly associated with AML; however, MS more commonly occurs after diagnosis of AML is previously established or after previous treatment of AML. Case Presentation: This case describes a patient with an atypical presentation of MS with no known history of AML and up to 18 lesions identified on CT scan that were previously being monitored for months by her primary care physician. She presented with sepsis attributed to choledocholithiasis versus bacteremia from scattered abscesses versus osteomyelitis of her left knee; nonetheless, lactic acid failed to improve after common bile duct stent with biliary sphincterotomy/dilation or with incision and drainage and empiric antibiotics. Core needle biopsy of her left abdominal sidewall was eventually positive for MS, but she unfortunately developed multiorgan failure with symptomatic hypercalcemia refractory to treatment and ultimately decided to go to comfort care rather than pursue further workup and treatment. Although bone marrow biopsy was ultimately not performed to rule out synchronous AML, this is likely a case of isolated MS due to her scattered skin lesions being present for months prior to hospitalization and acute illness. Conclusion: This case highlights the importance of maintaining MS in the differential diagnosis and the importance of early diagnostic core needle biopsy for patients with persistent skin lesions of unknown origin.