[Acute myelocytic leukemia (M0) in an elderly patient with relapsed granulocytic sarcoma (M7) of bone during the second period of complete remission 5 years after onset].

A 75-year-old man was admitted because of right knee joint pain in December 1999. He had suffered from acute myelocytic leukemia (AML: M0) in November 1994 and achieved the first complete remission (CR) then. His AML relapsed in August 1996, but fortunately he achieved a second CR. Radiographical bone examination revealed osteolytic lesions in his right knee and bone scintigraphy showed uptake in the right knee and the middle part of the left femur. MRI also revealed a low attenuation signal in the left femur. He had no abnormal findings in peripheral blood or bone marrow. Histological examination of the biopsied bone tissue showed a diffuse proliferation of round cells with medium-sized or large nuclei. These cells were histochemistrically negative for myeloperoxidase and naphtol-ASD-chloroacetate esterase, and were also negative for lysozyme, cytokeratin 7, 9, 20, EMA, CEA, CD3, CD79a on immunohistochemistry, but were positive for CD43, CD56. In immunophenotypic analysis of these cells by flow cytometry, CD7, CD13, CD33, CD41, CD56 were revealed to be strongly positive. On the basis of these findings we diagnosed these tumors as granulocytic sarcomas (GS), extramedullary recurrence of AML M7. Although radiation (36Gy) to these tumors brought a temporary relief of the pain, he died of systemic relapse of AML in February 2001. When presented CD7+ AML M0 had been diagnosed, but GS cells were also positive for CD 56 and CD41. Although CD56 had not been examined initially, he might have been had myeloid/NK cell precursor acute leukemia and CD41 might be acquired later in the course of the disease. It is known that AML M0, M7 and myeloid/NK cell precursor acute leukemia have poor prognoses, nevertheless he survived for 6 years. It may be that intensive and repeated chemotherapy for AML can obtain excellent outcome in the elderly cases in good systemic condition and with favourable prognostic factors.