RESUMEN
Although chronic myelogenous leukemia (CML) may be involved in any part of the body, infiltration of the body fluid has rarely reported in the literature. Here we report on a 35 year-old male patient who was diagnosed chronic myelogenous leukemia ten years previously and he received allogenic hematopoietic stem cell transplantation. He then presented with left knee pain eight years after the initial diagnosis. MRI revealed a soft tissue mass at the distal femur. Cytology of the joint fluid revealed myeloblasts, promyelocytes, eosinophilic myelocytes, band neutrophils, megakaryocytes and orthochromatic erythroblasts, which was all consistent with leukemic infiltration of the knee joint fluid. The immunohistochemistry was positive for CD34, CD117 and myeloperoxidase (MPO). Despite that the patient underwent radiation therapy, MRI revealed growth of the mass, and ten months later, the lymphoid blast phase of CML was confirmed after biopsy. The patient received an above knee amputation. Five months later, multiple masses were revealed on PET-CT at the left iliopsoas muscle, abdominal wall and bones. Bilateral pleural effusion occurred shortly after this. Cytologic evaluation of the pleural fluid also revealed blast-like cells, and histologic evaluation of the abdominal mass confirmed the lymphoid blast phase of CML with positivity for CD3, UCHL-1, CD34 and CD117, but negativity for MPO.