Clear cell sarcoma of tendons and aponeuroses with t(12;22) (q13;q12) diagnosed initially as malignant melanoma.

Cytogenetic analysis performed on a specimen from an inguinal lymph node metastasis of a tumor diagnosed initially as a cutaneous malignant melanoma revealed the following karyotype: 50,XX, +2, +7, +8, +8, t(12;22) (q13;q12). The finding of t(12;22) (q13;q12), an abnormality specific of clear cell sarcoma of tendons and aponeuroses (CCS), prompted reanalysis of histologic slides, and a final diagnosis of CCS was made. Our case illustrates the usefulness of cytogenetic analysis in the differential diagnosis of CCS and malignant melanoma. In addition, extra copies of chromosomes 8, 7, and 2, present in our case as well as in previously reported tumors, seem to play an important, although at present not understood, role in the development of CCS.