33714 Palisaded neutrophilic and granulomatous dermatitis in the setting of SRSF2-mutated chronic myelomonocytic leukemia: Case report and review of the literature

Abstract

Palisaded neutrophilic and granulomatous dermatitis (PNGD) is a rare cutaneous histopathologic reaction pattern associated with several underlying disorders. Few cases of PNGD have been associated with hematologic malignancies, in particular with chronic myelomonocytic leukemia (CMML), a malignant hematopoietic disorder with features of myeloproliferative neoplasm and myelodysplastic syndrome. CMML is characterized by peripheral blood monocytosis and bone marrow dysplasia, and can be supported by an acquired clonal cytogenetic abnormality most commonly in TET2, SRSF2, ASXL1, RUNX1, NRAS, and CBL. We present a patient with a papulosquamous rash on the neck, chest, and shoulders with histomorphological features on the spectrum of PNGD. Subsequent lab workup demonstrated a persistent mild monocytosis, raising concern for CMML. The patient was referred to hematology-oncology for a bone marrow biopsy, which ultimately led to her diagnosis. Cytogenic studies of the bone marrow biopsy demonstrated mutations in SRSF2, IDH2, and ASXL1, which were strongly supportive of this diagnosis. After discussion at a multidisciplinary tumor board, treatment directed at the skin eruption alone was recommended. She was started on prednisone taper and demonstrated marked clinical improvement. PNGD in the context of CMML has been scarcely reported, with only 4 prior reports in the literature. Our patient is the fifth reported case, and the fourth case with confirmed underlying SRSF2 mutation. This is likely a novel and reproducible clinical-histopathologic-molecular subtype of reactive granulomatous disease. The findings in this case strengthen the previously made association between PNGD and SRSF2-mutated CMML, and may help better define a unique recognizable subtype for dermatopathologists.