Chromosome changes in nonneoplastic tissue. Numerical and structural abnormalities in nasal polyps with atypical stromal cells

Cytogenetic abnormalities in Langerhans cell histiocytosis

We present the cytogenetic investigations of five histiocytic tumour lesions from children. In four cases there was a confirmed diagnosis of Langerhans cell histiocytosis (LCH) and one case of histiocytosis that did not fulfil all the criteria for true LCH. All five cases showed cytogenetic abnormalities, including the first report of an abnormal clone in LCH. The clone showed a t(7;12)(q11.2;p13) translocation and was detected in only a small percentage of cells. This case and a further three also contained non-clonal abnormalities and an increase in chromosome breakage. The fifth case, the only one in which no acquired abnormalities were seen, had a constitutional paracentric inversion of chromosome 13q.

Multiple polysomies in nasal polyps in children

Karyotyping of a nasal polyp from a 10-year-old girl revealed multiple numerical chromosome changes. Extra copies of chromosome 5, 7, 8, 12, 16, 17, 18, 19, 20, and 21 were present. Only one cytogenetically abnormal nasal polyp of a child has been reported in the literature. The karyotypes of the reported and the present case are remarkably similar. The significance of this finding in a nonneoplastic proliferation is discussed.