Sweet Syndrome-like Dermatosis as a Precursor to Overlapping Hematologic Malignancies: A Case Report and Review.

Sweet syndrome (SS) is a rare neutrophilic dermatosis often associated with hematologic malignancies, particularly myelodysplastic syndromes (MDSs). We report a case of SS-like dermatosis in a patient with MDS who subsequently developed peripheral T-cell non-Hodgkin lymphoma (NHL). We review the literature on Sweet syndrome to contextualize this atypical presentation We present a case report of a 77-year-old male with leukopenia and known MDS, admitted for a persistent, infiltrated erythematous eruption. The patient underwent repeated dermatologic assessments, and serial skin and bone marrow biopsies with histopathologic and immunohistochemical analysis. A literature review was also conducted, focusing on SS in association with hematologic malignancies, including T-cell NHL. Initial skin biopsies were inconclusive, and SS was diagnosed clinically based on lesion morphology and a prompt response to corticosteroids, despite the absence of definitive neutrophilic infiltrates. During follow-up, the patient's condition progressed with worsening cytopenias and recurrent febrile episodes. Repeat biopsies eventually confirmed the diagnosis of peripheral T-cell NHL with secondary hemophagocytic lymphohistiocytosis (HLH). This case illustrates the diagnostic uncertainty of SS-like eruptions in hematologic patients when histopathological findings are atypical or absent. Corticosteroid responsiveness may guide early diagnosis.