Henoch-Schonlein Purpura, an Unusual Presentation of Acute Myeloid Leukemia.

Background/aim: Acute myeloid leukemia (AML) is a hematologic malignancy that accounts for most annual deaths from leukemias in the United States. Although rare, cutaneous manifestations may be the first clinical sign of AML. Henoch Schonlein Purpura (HSP), as a manifestation of AML, has an unknown incidence. Here, we present a case of HSP as the presenting manifestation of AML.

Case Report: A 58-year-old woman presented to the Emergency Department with a rash and itching of all her extremities. The rash began on her thighs and arms a month prior and gradually spread distally. On presentation, she appeared alert and was hemodynamically stable. Skin examination revealed palpable purpura and plaques, with petechiae involving all extremities. Admission labs revealed a hemoglobin and hematocrit of 8 g/dl and 24% respectively. The white blood cell count was 1.23 k/mcl, absolute neutrophil count was 0.31 k/mcl, and platelets were 172,000 k/mcl. A broad work-up was carried out. Subsequently, skin and bone marrow biopsies were performed. Skin biopsy was positive for vascular immune reactivity with IgA, consistent with HSP. The bone marrow biopsy revealed hypocellular marrow with atypical blast infiltrates constituting 10-15% of cellularity, indicating AML. The patient was transferred to malignant hematology service where and started on induction chemotherapy for AML.

Conclusion: Prompt diagnosis and treatment of AML is crucial for better clinical outcomes. Our case suggests that HSP can be a rare presenting manifestation of AML. It is important to consider hematologic malignancy in patients presenting with HSP in the right clinical context as part of differential diagnosis.