Abstract

Chronic myelogenous leukemia(CML) is a clonal stem cell disorder, characterized by markedly increased myelopoiesis and the presence of the Philadelphia(Ph) chromosome. Ph chromosome, the result of a translocation between the abl proto-oncogene on chromosome 9 and the bcr gene on chromosome 22, is found in more than 95% of CML patients. The remaining 5% of patients are classified as Ph chromosome-negative CML and the bcr/abl gene rearrangement is detectable in approximately 50% of these patients. These Ph chromosome-negative, bcr/abl rearrangement-positive patients have clincal course and prognosis very similar to those of Ph chromosome-positive CML patients. We experienced a case of Ph chromosome-negative, bcr/abl rearrangement-positive CML presenting with multiple skin lesions and lymphadenopathy in a 59-years-old man. Bone marrow aspiration and biopsy showed typical features of CML in chronic phase. Skin and lymph node biopsies showed extramedullary leukemic cell infiltration, suggesting aggressive phase of CML. While the chramosome study revealed normal karyotype, RT-PCR analysis revealed bcr/abl fusion transcripts. In spite of chemotherapy, he expired 13 months after diagnosis.

• Keywords: CML, Dermopathy, Lymphadenopathy, Philadelphia chromosome, bcr/abl rearrangement, PCR