The clinical utility of conventional karyotyping in the detection of cytogenetic abnormalities in soft tissue tumours: an Asian institutional experience.

OBJECTIVES To assess the clinical utility of conventional karyotyping as a diagnostic tool in soft tissue tumours amidst the increasing use of molecular cytogenetics. DESIGN Case series. SETTING Singapore General Hospital, an Asian institution. PARTICIPANTS A total of 35 participants (18 male and 17 female) aged 15 to 81 years were included in this study. Conventional karyotyping of 35 consecutive fresh soft tissue tumour specimens was performed over 4 years and the results were analysed. RESULTS Of the 35 cases of soft tissue tumours reviewed, chromosome abnormalities were detected in 22 (63%) cases, 11 (31%) showed a normal karyotype, and 2 (6%) had culture failure. Of the 22 cases with abnormal karyotype, nine (41%) cases showed recurring aberrations: Ewing's sarcomas (n=2), desmoplastic small round cell tumour (n=1), synovial sarcomas (n=3), myxoid liposarcomas (n=2), and lipoma (n=1). One lipoma case had a t(2;12)(q23;q15) in which 2q23 breakpoint was not reported before. Chromosomal aberration involving 12q15 breakpoint has been shown in a previous study to be indicative of a lipoma-like liposarcoma. Another lipoma case had addition of 5q15 and 9p13 together with a balanced aberration of t(12;13) (q13;q12) which were novel aberrations. One synovial sarcoma case showed t(3;7)(q21;p13) which was an uncharacteristic aberration. CONCLUSION Conventional karyotyping demonstrated utility as a genome-wide screening tool for soft tissue tumours and an adjunct diagnostic tool in the event histopathology results were doubtful. With the more widespread use of karyotyping, novel recurring chromosomal aberrations may be discovered.