Conference Abstracts - 2025 Summit on Hematologic Cancers
Vol. 5, Issue Supplement 1, 2025 · S1-2
Myeloid Dermatoses Preceding a Diagnosis of Myelodysplasia: Leukemia Cutis or Sweet syndrome?
Evani Patel, MD,Ajit Singh, MD,Douglas Beach, MD,Gabriel Caponetti, MD
Submission received: 2025-07-10 / Accepted: 2025-07-28 / Published: 2025-09-15
Abstract
Dermatologic pathologies are sometimes the first presenting sign of an occult hematological malignancy. Myeloid dermatoses, associated with myelodysplastic Syndrome (MDS) or acute myeloid leukemia (AML), can include leukemia-cutis (LC) and Sweet syndrome (SS). These subtypes share clinical and histological similarities, making diagnostic work-up challenging, especially in the setting of an unwell patient without a known pre-existing malignancy. We present a unique case of a patient presenting with violaceous plaques that were later biopsied to confirm acute febrile neutrophilic dermatosis consistent with SS. This clinical clue provided evidence toward an eventual diagnosis of new high-risk MDS leading to AML transformation.
Case Presentation
A 53-year-old female presented with two days of right lower leg rash, described as an indurated, irregular, pink, tender plaque on a background of hyperpigmented, blanchable patch. On admission, she was afebrile and normotensive. Lab work was most notable for elevated inflammatory markers, and a CBC with new anemia at hemoglobin 7.6g/dL. Ultrasound of the right extremity was negative for DVT, and CT of the leg showed extensive soft-tissue edema. She was started on antibiotics for suspected cellulitis. Despite this, she developed worsening leukocytosis, anemia, and thrombocytopenia. Given persistent leg allodynia, a punch biopsy of her leg rash was performed and showed a nonspecific perivascular infiltrate of neutrophils. Immunohistochemistry showed rare CD117+/CD34- blastoid cells. Follow-up peripheral blood flow cytometry showed a 6% discrete myeloblast population. Bone marrow biopsy confirmed high-risk myelodysplastic syndrome with NPM1, DNMT3A, and NRAS mutations. 6 months later, she had transformation into acute myeloid leukemia (AML). She underwent two cycles of azacitadine-venetoclax with partial response and was then transitioned to decitabine before ultimately passing away from hypoxic respiratory failure.
Discussion
SS presents as painful papules with neutrophilic infiltration and is usually reactive, whereas LC involves leukemic blast infiltration clonally identical to bone marrow AML. Diagnosis of LC and SS is challenging as they share many similar clinical similarities, but can provide insight into the tempo of progression. Molecular subtyping is imperative in helping distinguish clonality; however, the presence of mixed phenotypes in CD117/CD34 can also complicate diagnosis, as it did with our patient. Multi-disciplinary management with punch biopsies should not be delayed if rashes persist. Finally, if SS is suspected, LC should always be considered in the differential diagnosis.
References
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