Abstract Introduction Sweet Syndrome (acute neutrophilic dermatosis) is a rare inflammatory condition characterized by fever, tender erythematous plaques, and dermal neutrophilic infiltrates on histology. It may occur secondary to malignancy and can involve extracutaneous organs. We present a case of Sweet Syndrome with pulmonary involvement in a patient with myelodysplastic syndrome (MDS). Case Presentation A 67-year-old man with MDS presented with fever, erythematous skin lesions, and cough one week after receiving Decitabine. On admission, his temperature was 102.7 °F, and he had violaceous papules on the left hand and arm. He subsequently developed dyspnea requiring supplemental oxygen. Laboratory studies showed profound pancytopenia. Chest X-ray revealed reticulonodular opacities, and CT imaging demonstrated broncho-pneumonic infiltrates with tree-in-bud nodularity, raising suspicion for bacterial or fungal pneumonia. Broad-spectrum antibiotics and antifungal agents were initiated. However, the simultaneous appearance of skin lesions raised concern for disseminated fungal infection versus pulmonary Sweet Syndrome. Skin biopsy revealed perivascular and interstitial neutrophilic dermatitis, confirming Sweet Syndrome. High-dose IV steroids were started, leading to rapid clinical improvement and near-resolution of pulmonary infiltrates on repeat CT within five days. Planned bronchoscopy was deferred due to clinical and radiologic improvement. In the absence of an infectious source and with a robust steroid response, along with skin histological findings, pulmonary Sweet Syndrome was diagnosed. Discussion Pulmonary involvement is a rare, potentially severe manifestation of Sweet’s syndrome characterized by sterile neutrophilic infiltration of the lung parenchyma which typically presents as acute respiratory symptoms such as dyspnea, cough, and hypoxemia, often accompanied by fever. Imaging may reveal pulmonary infiltrates, which can be mistaken for infectious pneumonia. Histopathology of affected lung tissue or bronchoalveolar lavage demonstrates sterile, neutrophilic infiltration without evidence of infection or vasculitis in most cases, mirroring the cutaneous findings. Pulmonary Sweet syndrome may precede, coincide with, or follow the appearance of characteristic skin lesions, and can be associated with underlying hematologic malignancies or other systemic diseases. The mainstay of treatment is systemic corticosteroids, which typically result in rapid clinical and radiographic improvement. Early recognition is critical, as untreated pulmonary involvement can progress to respiratory failure and multi-organ dysfunction. This case underscores the importance of considering pulmonary Sweet Syndrome in the differential diagnosis of neutropenic fever with pulmonary infiltrates in patients with underlying malignancy. This abstract is funded by: None
Pineau et al. (Fri,) studied this question.