From Skin to Blood: Ulcerative Pyoderma Gangrenosum Unveiling Acute Myeloid Leukemia.

While Pyoderma gangrenosum (PG) is commonly associated with hematological disorders such as acute myeloid leukemia (AML), it typically presents concurrently with the hemopathy, mostly in its bullous form, among middle-aged individuals. Here, we report the unusual case of a young female patient who presented with PG in its ulcerative form, three weeks before the onset of AML. A 31-year-old female presented with a one-week history of painful perianal papulopustule that evolved into an irregular ulceration with violaceous borders, mucopurulent serosity, and erythematous surrounding skin. Laboratory work-up demonstrated elevated inflammatory markers and hyperleukocytosis, with no cytopenia, and normal peripheral blood smear. Two weeks later, the ulcer growth was noted with a similar ulceration at a venipuncture site. A complete blood count revealed pancytopenia, with 45% blasts on the peripheral blood smear. Skin biopsies showed an aseptic neutrophilic infiltrate in favor of PG. Intravenous methylprednisolone was administered with rapid resolution of the lesions. However, the patient died shortly after. The post-mortem results of bone marrow aspirate revealed AML, with immunohistochemistry of the skin lesions confirming the clonality of neutrophils derived from the leukemic clone.  This case highlights a distinctive clinical presentation, illustrating the manifestation of PG three weeks before the onset of AML in its ulcerative rather than bullous form, in a young female patient.