Multiple Granulocytic Sarcomas in Essential Thrombocythemia

A 59-year-old woman was diagnosed with essential thrombocythemia in 1988 and had been treated with hydroxyurea, mitobronitol, busulfan, and ranimustine, in that order. Hepatosplenomegaly, low-grade fever, and body weight loss manifested, and a few blasts were noted in the peripheral blood studied in March 2002. A biopsied specimen of the bone marrow showed myelofibrosis but not a leukemia in August 2004. An abnormal karyotype with der(1; 13) appeared for the first time. She was treated with low-dose prednisolone. In January 2005, she experienced left hip joint pain, and magnetic resonance scanning showed a tumoral lesion in the femoral head. Histological diagnosis of the biopsied mass revealed that it was a granulocytic sarcoma, and radiotherapy was performed. In April 2005, bone scintigraphy showed multiple lesions. She became febrile and red blood cell transfusion-dependent with hepatosplenomegaly and a small number of circulating blasts. Intravenous cytarabine (low dose) and etoposide relieved the fever and hepatosplenomegaly; however, she developed a pathologic fracture of the right humerus. An additional karyotypic abnormality (7q22 deletion) was noted. She subsequently died of infection. Granulocytic sarcoma is very rare in essential thrombocythemia, and this patient may be the first reported case of essential thrombocythemia that developed multiple lesions and a pathologic fracture without transformation to overt leukemia.