C51-33 Pus, Pancytopenia and Pulmonary Failure: A Lethal Masked Malignancy

Abstract Introduction Acute myeloid leukemia (AML) is an aggressive hematological malignancy, which may present with vague constitutional symptoms or mimic infectious processes, particularly in immunocompromised individuals. While classic presentations include fatigue, fever, and leukocytosis, early signs are often misattributed to neutropenic sepsis. In particular, pulmonary leukemic infiltrates can resemble pneumonia or acute respiratory distress syndrome. We present a case of a middle-aged man with a rapidly progressive clinical course where presumed hidradenitis suppurativa and sepsis ultimately unmasked a new diagnosis of AML complicated by leukemic pulmonary infiltrates. Description A 49-year-old male with diabetes mellitus presented with three days of high-grade fevers, chills, diaphoresis, and generalized weakness. He reported a painful, tennis ball sized swelling in the left axilla that developed over three weeks. This swelling spontaneously ruptured, initially draining pus, followed by copious blood. He also noted left submandibular swelling and poor appetite, but denied weight loss or other constitutional symptoms. Initial labs noted pancytopenia (WBC 2.79, RBC 2.68, PLT 15). CT of the axilla revealed soft tissue stranding, edema, and a focus of gas concerning for subcutaneous emphysema. Chest CT showed diffuse interlobular septal thickening, patchy peribronchial ground-glass opacities, and shotty mediastinal and bilateral hilar lymph nodes. Abdominal imaging was significant for splenomegaly (15.5 cm). He was admitted with presumed neutropenic sepsis secondary to hidradenitis suppurativa complicated by abscess. He was treated with piperacillin-tazobactam and vancomycin and required red blood cell and platelet transfusions. Flow cytometry was suspicious of leukemia with 52% of monocytic blasts; bone marrow biopsy confirmed AML. The patient was transferred to the intensive care unit for acute hypoxemic respiratory failure presumed secondary to leukemic infiltrates. Induction chemotherapy with cytarabine and daunorubicin was initiated. Despite aggressive measures, he rapidly decompensated, requiring intubation and vasopressors. However, despite aggressive support, the patient was later found pulseless, and cardiac standstill was confirmed on point-of-care ultrasound. Discussion This case highlights how undifferentiated sepsis may obscure the diagnosis of hematologic malignancy. Leukemic pulmonary infiltrates may mimic pneumonia radiographically and clinically, further delaying the diagnosis. AML can masquerade as an infection until respiratory failure and multiorgan collapse ensue. Early diagnosis is crucial, as outcomes remain poor once respiratory failure develops. There should be a high index of suspicion for hematologic malignancy in patients presenting with sepsis and unexplained cytopenias, atypical radiographic findings, or splenomegaly. Our patient’s fulminant course underscores the need for early diagnostic consideration of hematological malignancy in atypical presentations. This abstract is funded by: None