Cytogenetic analysis of short-term cultures from 6 tumors of the nasal cavity and paranasal sinuses--one esthesioneuroblastoma, 2 adenocarcinomas and 3 squamous-cell carcinomas (SCC)--revealed clonal chromosome aberrations in all cases. The esthesioneuroblastoma had a complex hyperdiploid karyotype. None of the aberrations was similar to those previously described in short-term cultures or established cell lines from esthesioneuroblastomas. The 2 adenocarcinomas had complex karyotypic changes, which in both cases included rearrangements of bands 9p22 and 14q11. One SCC had 5 unrelated pseudodiploid clones, 1 displayed a highly complex karyotype, including rearrangement of band 11q13, and 1 had simple karyotypic changes with loss of 6q material and gain of 3q. These findings are similar to those described in head-and-neck SCC at other sites.