Malignant fibrous histiocytomas with a 19p+ marker chromosome have increased relapse rate.

Malignant fibrous histiocytomas (MFH) often have complex karyotypic abnormalities. Recently, we described a 19p+ marker chromosome in 9 of 22 MFH. Other recurrent karyotypic features have been telomeric associations, ring chromosomes, and structural rearrangements of chromosomal bands 1q11, 3p12, and 11p11. After a median follow-up time of 18 months, distant metastases and/or local recurrence have occurred in 8 of the 9 patients with 19p+ markers but in only 4 of the 13 patients without. The only other cytogenetic parameter that seemed to affect relapse tendency was the presence of ring markers: relapse has occurred in 2 of 8 patients with unidentifiable supernumerary ring marker chromosomes compared to 10 of 14 patients without. No differences in relapse frequency were apparent for tumors belonging to the other cytogenetic subgroups. It thus appears that 19p+ marker chromosomes in MFH signal an increased relapse risk whereas the finding of ring markers indicates a reduced relapse risk.