Intratumoral cytogenetic heterogeneity in a benign neoplasm.

Cytogenetic findings are reported in a 64-year-old man who had a history of rapid growth of a mass in the left groin area. The histopathologic diagnosis of the tumor was consistent with that of a lipoma with atypia. Cytogenetic analysis was done on an incisional biopsy specimen. The initial biopsy specimen revealed, in addition to normal cells, three different clones: 46,XY,t(12;21)(q13;q21), 46,XY, t(2;12)(q11.2'1.2), t(19;20)(q13.1'3), and 47.XY,+ r. The subsequently excised specimen showed a normal male karyotype (46,XY) and a predominant clone with the karyotype, 47,XY,t(2;12)(q11.2'1.2),t(3;11)(p24'5), + r. One cell with 47,XY, + r was present. In addition, polyploid cells with large markers, rings, and a high frequency of telomeric associations were also observed.