2002 CTOS Annual Meeting Posters — Pathology

CYTOGENETIC ANALYSIS OF 29 MYXOID/ROUND CELL LIPOSARCOMAS
[Abstract ID: 47]

Category: Pathology

Authors: Brian P Rubin¹, Christopher B Hagen¹, Thomas H Norwood¹, Christine M Disteche¹, Karen Swisshelm¹, Scott M Schuetze¹, Janet F Eary¹, James D Bruckner¹, Ernest U Conrad¹

Author Institutions: ¹University of Washington Medical Center, Washington, United States

Presenter: Brian P Rubin
bprubin@u.washington.edu

Correspondent: Brian P Rubin
bprubin@u.washington.edu
Seattle Washington United States 98195
Ph: 206-598-5024
Fax: 206-598-8697

Objectives: Myxoid/round cell liposarcoma is one of the most common sarcomas. Most cases possess a characteristic t(12;16)(q13;p11) which results in fusion of the CHOP and FUS genes. This translocation is thought to be central to the pathogenesis of myxoid/round cell liposarcoma. However, little is known about secondary cytogenetic changes. It is the purpose of this study to characterize the cytogenetic findings in a large series of myxoid/round cell liposarcomas.

Methods: 29 myxoid/round cell liposarcomas were karyotyped over an eight year period. These karyotypes were analyzed by standard methodology for the presence of the characteristic t(12;16)(q13;p11) as well as other cytogenetic aberrations.

Results: The t(12;16)(q13;p11) was identified in 25 of 29 cases and was the sole cytogenetic aberration in nine cases. Gains as well as losses of chromosomal material were also seen. The most common secondary changes were trisomy 8 (5 cases), monosomy 7 (3 cases), trisomy 5 (2 cases), monosomy 8 (2 cases), monosomy 15 (2 cases), and monosomy 22 (2 cases).

Conclusions: The t(12;16)(q13;p11) is a sensitive marker for myxoid/round cell liposarcoma, occurring in 86% of cases in the current series. Other cytogenetic changes are frequent and are identified in 72% of cases. The most common secondary changes are trisomy 8 and monosomy 7, which were seen in 17% and 10% of cases respectively. We are currently obtaining follow-up data on this series of patients with myxoid/round cell liposarcoma to see if secondary cytogenetic changes correlate with clinical behavior.