Consistent Involvement of Chromosome 13 in Angiolipoma

Angiolipoma is a rare benign soft tissue tumor composed of mature adipocytes and blood vessels. Genetic information on angiolipomas is scarce. With the single exception of one tumor which carried a t(X;2)(p22;p12), all angiolipomas hitherto investigated cytogenetically had normal karyotypes.

G-banding chromosome analysis was performed on three short-term cultured angiolipomas. Fluorescence in situ hybridization (FISH) analysis using a commercially available RB1 deletion probe was also done.

All three angiolipomas had abnormal karyotypes with loss or structural rearrangement of chromosome 13. The first tumor had the karyotype 46,XY,-6,del(13)(q14),+mar[cp5], the second had 44~45,XY,t(1;10;15)(p21~22;q24;q24),-13[cp5], and the third karyotype was 43,XX,t(13;22;17) (q12;q13; q22~23)[14]. FISH analysis showed heterozygous and homozygous deletion of the RB1 probe in case 2 and 3, respectively. FISH analysis failed in case 1.

Chromosome 13 was consistently involved in all three angiolipomas.