[Appearance of Sweet's syndrome in a patient with myelodysplastic syndrome (MDS) without relation to the hematological findings of MDS].

Sweet's syndrome is known often to associate with non-lymphocytic leukemia (ANLL); however, there have been very few reports of Sweet's syndrome associated with myelodysplastic syndrome (MDS). It was reported that improvement and exacerbation of these two syndromes occurred simultaneously. We present here a 49-year-old male with Sweet's syndrome developed in RAEB in T. He complained of fever and infiltrative eruptions on the trunk and legs. At the time of admission to Tsukuba University Hospital, the peripheral blood showed leukocytopenia (WBC 2,000/microliter: Blast 9%, PMN 51%) and anemia (Hb 6.5 g/dl). Pseudo-Pelger anomaly of neutrophils was found on the blood smear. From the hematological findings and the result of skin biopsy, the patient was diagnosed as having MDS (RAEB in T) complicated by Sweet's syndrome. Prednisolone was effective to improve his fever and eruptions. However, when treated with low-dose Ara-C and when transformed into acute myelogenous leukemia, there was no correlation between the condition of Sweet's syndrome and the percentages of blasts in the marrow. We suggest that eruptions of Sweet's syndrome associated with MDS are not always a good index of exacerbation of MDS.