Marker ring chromosome--a new cytogenetic abnormality characterizing lipogenic tumors?

We have analyzed three intramuscular lipomas, two atypical and one with ordinary benign histology, as part of a systematic study of the karyotypic characteristics of mesenchymal tumors. A large ring chromosome of uncertain origin, but possibly representing a rearranged chromosome #3, was found in all three tumors. Previous reports on the chromosome banding pattern in lipogenic neoplasms are restricted to only three cases, all liposarcomas. In one of these, a well differentiated liposarcoma, a ring chromosome was described that was remarkably similar in morphology to the aberration reported here. We conclude that this ring chromosome may constitute a characteristic cytogenetic marker for lipogenic tumors.