Childhood intramuscular lipoma with a novel three way translocation. a case report

Abstract

Lipomas are common benign adipocyte tumours of adults, and frequently exhibit clonality, with karyotypic anomalies occurring in approximately two-thirds of adult cases. In contrast, lipomas are exceptionally rare in childhood. We describe an intramuscular lipoma in the back of a healthy 5-year-old boy, with the initial MRI examination showing features suspicious of rhabdomyosarcoma. An incisional biopsy and a subsequent excisional biopsy were performed and both confirmed the lesion to be a lipoma. Cytoge-netic analysis demonstrated a three way translocation involving chromosomes 8q12, 17q25 and 13q14. The 8q11–13 breakpoints are common in lipoblastomas, but are rare in lipomas. It has been postulated that rearrangements involving this chromosomal breakpoint is associated with up-regulation of the PLAG1 gene. The 13q14 breakpoint is associated with a subset of lipomas, usually involving deletion of material from 13q with a minimal region of deletion identified in band 13q14. Our patient’s karyotype does not show a visible deletion, therefore a molecular technique would be required to investigate the possibility of submicroscopic deletion or rearrangement at this site. Lipomas in childhood are known to occur as part of the Bannayan-Riley-Ruvalcaba syndrome and Aicardi syndrome. Our patient is a normal, healthy 5-year-old child.