Cytogenetic and molecular evidence of marrow involvement in extramedullary acute myeloid leukaemia

• Published in: British journal of haematology 2000-09, Vol.110 (3), p.547-551
• Main Authors: Lillington, Debra M., Jaju, Rina J., Shankar, A. G., Neat, Michael, Kearney, Lyndal, Young, Bryan D., Saha, Vaskar
• Format: Article
• Language: English
• Subjects: Acute Disease; AF10; Artificial Gene Fusion; Biological and medical sciences; Bone Marrow Cells; Chromosomes, Human, Pair 5; DNA-Binding Proteins - genetics; Electrophoresis, Agar Gel; Female; Gene Rearrangement; granulocytic sarcoma; Hematologic and hematopoietic diseases; Hematology; Histone-Lysine N-Methyltransferase; Humans; In Situ Hybridization, Fluorescence; Infant; Karyotyping; Leukemia, Myeloid - genetics; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Medical sciences; medullary disease; MLL; Myeloid-Lymphoid Leukemia Protein; Proto-Oncogenes; Reverse Transcriptase Polymerase Chain Reaction; Transcription Factors - genetics
• ISSN: 0007-1048; 1365-2141
• DOI: 10.1046/j.1365-2141.2000.02212.x

A diagnosis of granulocytic sarcoma was made in a 2‐year‐old child based on the detection of myelomonocytic blasts in tissue obtained from a subcutaneous nodule with no evidence of concomitant disease in the bone marrow. The child responded to systemic chemotherapy and is in remission 3 years later. An identical clone with an in frame fusion of the MLL and AF10 genes was identified from both tissue and bone marrow samples. The generation of an in frame MLL–AF10 fusion requires complex intra‐ and interchromosomal exchanges between chromosomes 10 and 11. In this case, an intrachromosomal rearrangement of chromosome 5 was also observed. This case illustrates the presence of systemic disease in extramedullary leukaemia, its response to systemic rather than topical therapy and suggests that the events leading to chromosomal translocations in leukaemia may be part of a generalized intracellular event.