High incidence of 17p13 chromosomal abnormalities in malignant histiocytosis.

Cytogenetic analyses of three patients during autopsy who had a pathologic diagnosis of malignant histiocytosis and of one patient who was strongly suspected to have malignant histiocytosis because of her clinical and hematologic findings were done. All three patients studied with bone marrow specimens showed polyploidy (3.4-20%). Two of three patients with chromosomal abnormalities showed 17p+ markers with a breakpoint at 17p13. Seven of 22 previously reported malignant histiocytosis patients (32%) with descriptions of detailed whole karyotypes have the 17p+ markers, including two of the authors' patients. Five of seven patients with 17p+ involved 17p13. Although breakpoints at the 17p+ in the remaining two were not described, their karyotypes were shown to possibly involve 17p13. The high incidence of this abnormality is not considered accidental, and this breakpoint is not usual in many other neoplastic disorders. These facts may indicate that 17p13 chromosome abnormality is a specific change of malignant histiocytosis.