CYTOGENETIC BICLONALITY CORRESPONDING TO MULTIPHASIC DIFFERENTIATION IN AN ATYPICAL THYROID ADENOMA

Cytogenetic aberrations have been described in about 30% of benign thy roid tumors, but their role for tumorigenesis or progression has not y et been elucidated. We describe the cytogenetic analyses in a thyroid adenoma with two different clonal cytogenetic stemlines: 45,XX,der(1)t (1;14)(p13;q11.2 -(q3.3),t(5;12)(q11.2;q24),del(9)(q12), 9)(p15;q13),d er(14)t(14;15)(q13;q23),del(15)(q23), q13)/46,X,?inv(x),?inv(3)(p21q29 ),t(3;8)(q26;q12). Histologic examination revealed an atypical follicu lar thyroid adenoma containing microfollicular, follicular, trabecular -solid, and oncocytic components. There may be a direct relation betwe en the different cytogenetic stemlines and the histologic diversity of the tumor. Thyroid tumors with complex karyotypes involving the 19q13 breakpoint may represent advanced stages of karyotypic evolution and therefore warrant an extensive clinical follow-up.