Pericentric inversion (12)(p12q13-14) as the sole chromosomal abnormality in a leiomyoma of the vulva.

We present a case of a leiomyoma of the vulva with karyotype 46,XX,inv(12)(p12q13-14). It is noteworthy that the breakpoint at 12q13 approximately q14 is flanked by the HMGA2 gene. Although the gene remained intact, the presence of HMGA2 protein in the neoplastic cells indicates that it became activated by the rearrangement. It is curious that activation of the HMGA2 gene, while not restricted to smooth muscle tumors, was so far found only in genital leiomyomata (uterus, vulva, vagina) and not in any smooth muscle tumors arising in extragenital locations.