Thyroid nodular hyperplasia: chromosomal studies in 14 cases.

Cytogenetic study of 14 thyroid nodular hyperplasias revealed a hyperdiploid karyotype in two cases (14%) and a normal chromosomal complement in the remaining cases. Some of the numerical alterations found were identical to the ones considered characteristic of a subset of thyroid adenomas (+5, +7, +9, +12, +14, and +16). Our findings suggest that the cytogenetic events involved in the pathogenesis of thyroid hyperplastic lesions and benign tumors may be closely related, which supports the hypothesis of a biologic "continuum" between these two types of lesions.