Paragangliomas. Static cytometric studies of nuclear DNA patterns.

BACKGROUND

The biologic behavior of most paragangliomas cannot be predicted from their histologic appearance. Recently, cytometric studies have found an association between an aggressive clinical behavior and the presence of a hyperdiploid or tetraploid range in the DNA nuclear content.

METHODS

The authors have studied morphometric (nuclear area and nuclear form factor) and DNA densitometric (integral optical density and DNA ploidy) features of 23 cases of paraganglioma by means of slide cytophotometry with the microTICAS system (University of Chicago, Chicago, IL). The samples were selected from paraffin-embedded tissue, and representative sections were stained with the Feulgen technique. The differences between groups (cervical versus extracervical paragangliomas) were investigated with the Mann-Whitney test and Fisher discriminant linear function.

RESULTS

The densitometric study showed aneuploid cell lines in 15 of 16 noncervical paragangliomas (with a DNA index within the tetraploid range), whereas 3 of 7 cervical paragangliomas were aneuploid and only 1 case did not have not a diploid cell line (with a DNA index within the peridiploid range). Mean ploidy (4.33 arbitrary units [AU] and 2.72 AU, respectively), nuclear area (58.74 microns 2 and 32.08 microns 2, respectively), the minor and major DNA indices (1.09-1.24 and 1.83-1.96, respectively), and DNA content variability (2c deviation indices [2cDI] of 8.62 and 1.88 AU, respectively) were higher in noncervical paragangliomas. With Fisher linear discriminant function, mean nuclear area (P = 0.0008), 2cDI (P = 0.0030), and the minor DNA index of each cell proliferation were correlated with location. None of the variables established statistically significant differences in comparisons of malignant and benign paragangliomas.

CONCLUSIONS

Karyometric and DNA densitometric parameters have limited value in determining the prognosis of paragangliomas, although they are correlated with tumoral location, which is still an indicator in establishing the prognosis of these neoplasms.