[Successful treatment of an essential thrombocythemia patient complicated by Sweet's syndrome with combination of chemotherapy and lenalidomide].

A 79-year-old man had been followed up since July 2003 based on a diagnosis of essential thrombocythemia (ET). The patient visited our hospital after developing a high fever and rash in August 2010, and Sweet's syndrome was diagnosed based on skin biopsy results. The bone marrow aspirate showed features like those of myelodysplastic/myeloproliferative neoplasm (MDS/MPN, unclassifiable). Administration of metenolone and azacitidine was initiated in March and May 2011, respectively, but the rash associated with Sweet's syndrome showed exacerbation. Ranimustine was therefore administered starting in July 2011 to control the blood cell count, but the rash associated with Sweet's syndrome persisted. Combination therapy with lenalidomide was initiated in September 2012, and resulted in control of the blood cell count and marked improvement of Sweet's syndrome.