Loss of chromosome 13 material in cellular angiofibromas indicates pathogenetic similarity with spindle cell lipomas

Background: Cellular angiofibroma is a rare benign mesenchymal neoplasm with morphological and immunohistochemical similarities to spindle cell lipoma. Karyotypic information on cellular angiofibroma is restricted to one case only which showed loss of material from chromosomes 13 and 16. A few other studies using fluorescence in situ hybridization showed deletions of the RB1 and FOXO1 loci, both of which are located in chromosome band 13q14. We present here cytogenetic data on two cellular angiofibromas with an abnormal karyotype. Methods: G-banding and fluorescence in situ hybridization (FISH) analyses were done on two cellular angiofibromas. Results: In both tumors, a rearrangement leading to loss of chromosome 13 material was seen, together with other structural chromosome abnormalities. FISH analysis showed heterozygous deletion of the RB1 locus (13q14) in both cases. Conclusion: Our results demonstrate loss of chromosome 13 material in cellular angiofibroma, though not as the sole cytogenetic change, confirming the (cyto)genetic similarity of these tumors with spindle cell lipomas.