Objective: To test the discriminatory capability of nuclear features in the subclassification of rhabdomyosarcoma (RMS) and especially to differentiate embryonal from alveolar RMS.
Study design: The study included 42 patients with RMS. We performed the analysis on Feulgen-stained filtrates of cell suspensions prepared from deparaffinized tissue sections. Image analysis was performed by an automated, high-resolution image cytometer on at least 200 nuclear images. Photometric, morphometric and nuclear texture features were analyzed. Probability density distributions were calculated for each nuclear feature of individual RMS subgroups and compared in order to detect possible differences.
Results: There were significant differences between embryonal and alveolar RMS in five nuclear features: DNA index, sphericity, elongation, low_DNA_area and fractall_area. We were able to differentiate between the two main RMS subgroups in 82% of cases on the basis of either sphericity or elongation alone, while the power of differentiation for texture features was 72-79%.
Conclusion: Differentiation between embryonal and alveolar RMS using one nuclear feature is not an important adjunct to light microscopy. However, the possibility of using a combination of nuclear features would probably increase the discriminatory ability.