A case of virilizing ovarian Sertoli-Leydig cell tumor overexpressing the BCL2 gene and including a novel clonal chromosomal rearrangement of chromosome 18, der(5)t(5;18)(p13;q12),+6,+12, der(18)r(5;18)(p15.3p13;p11.3q12) is described. Further studies of these rare tumors are necessary to ascertain the significance of the findings.