Cytogenetical findings of recurrent meningiomas. A study of 10 tumors.

Cytogenetic analyses of 10 cases of recurrent meningiomas growing in culture between 1-10 days are reported, of which seven showed benign morphology, one atypical, and two, malignant features. Normal karyotypes with nonclonal alterations were found in three cases, one case with only monosomy 22, and complex karyotypes in the remaining six. Four cases were hypodiploid, one pseudodiploid, and one hyperdiploid. The chromosomes most often involved in structural rearrangements were 1, 7, and 14 and the losses were chromosomes 7, 10, 14, 15, 18, and 22. Ring chromosome, dicentrics, double minutes, and association between satellites were found in one case. These complex karyotypes with hypodiploidy, structural rearrangements, and other markers in recurrent meningiomas may indicate aggressive tumor characteristics.