NEW HISTOPATHOLOGIC DATA OF PROGNOSTIC VA LUE IN EXTRAADRENAL PARAGANGLIOMAS - STUDY OF 9 CASES

BACKGROUND: The biological behavior of paragangliomas is difficult to evaluate by classic histological criteria thus justifying the use of i mmunohistochemical markers as prognostic factors. METHODS: Nine extraa drenal paragangliomas (three jugulotympanic, four carotid-body tumors, and two retroperitoneal) were studied by conventional histological cr iteria, and also by chromogranin A and neuron-specific enolase (NSE) i mmunohistochemical staining for the study of chief cells, and S-100 as a marker of sustentacular cells. The rate of cell proliferation was s tudied by the proliferating cell nuclear antigen (PCNA). The correlati on between these parameters and the clinical evolution of the neoplasm s, which were classified as benign, locally aggressive, and malignant (with metastasis), were also analyzed. RESULTS: The atypia and the mit otic rate did not correlate with the behavior of the tumor. Less immun ostaining with the anti-S-100 and anti-chromogranin A antibodies was o bserved in the malignant paragangliomas and in those which were locall y aggressive. In the benign tumors the proliferative rate (PCNA) oscil lated between 0.7 % and 3.7 %, and 40 or less PCNA positive cells were counted in 10 high-power field (HPF) (40x). In malignant and locally aggressive tumors the proliferative rate was 5 % or more, with 60 or m ore cells that were positive for PCNA being found in 10 HPF. CONCLUSIO NS: The histopathologic signs implying worse prognosis in extraadrenal paragangliomas are a decrease in chromogranin A and S-100 immunoreact ivity and a rate of cell proliferation of 5 % or greater, or a number of cells stained for proliferating cell nuclear antigen greater than 5 0 in 10 high-power field.