Myeloid Sarcoma of the Testis and Skin With Osteolytic Bone Lesions in Blastic Transformation of Primary Myelofibrosis

Myeloid sarcoma is a localized tumor composed of myeloblasts and other immature myeloid cells outside the bone marrow. It is usually associated with acute myeloid leukemia and rarely with chronic myeloproliferative disorders. We present a 43-year-old male who developed a solitary tumor in his left testis 6 years after an initial diagnosis of primary myelofibrosis. Four months later, another infiltrative tumor in the skin overlying his left wrist was discovered. After orchiectomy, the immunohistochemistry revealed tumor cells expressing LCA, CD34, CD117, MPO, CD15, lysozym, and CD43+, which confirmed diagnosis of myeloid sarcoma. The histologic and immunohistochemical findings were similar. The patient was treated with local radiotherapy to the skin tumor site, resulting in regression of the tumor and with chemotherapy when acute myeloblastic leukemia developed. The patient survived 21 months after initial presentation.