Studies for estimating the biologic behavior and prognosis of paragangliomas in the head and neck

Despite a large number of histopathologic and immunohistochemical studies, the biologic behavior and prognosis of paragangliomas (glomus tumors) of the head and neck still remain uncertain. In the present study 36 specimens from 32 patients who underwent surgery for a paraganglioma were examined. The examinations included routine histology, quantitative DNA analysis based on image cytometry, immunohistochemical detection of the proliferating cell nuclear antigen (PCNA) along with visualization of nucleolar organizer regions (AgNOR). According to LeCompte, the paragangliomas were histologically divided into three subcategories: 16 patients had a paragangliomatous tumor. 14 patients had an adenomatous tumor, and 6 patients had an angiomatous tumor. Quantitative DNA analysis revealed three categories of tumors with characteristical DNA pattern; DNA type I tumors were pure diploid, DNA type II tumors had stemlines at 2c and 4c and were therefore recognized as diploid-tetraploid. Aneuploid cells were not apparent in these two groups. DNA type III tumors had stemline ploidies exceeding 2c and 4c. Aneuploid cells were present in all of these tumors. The biologic behavior of these lesions therefore must be recognized as suspicious. DNA type III tumors and adenomatous tumors showed the highest values for the PCNA scores, indicating a higher proliferation rate and a more rapid growth pattern in these lesions. Twenty patients could be followed over a period of up to 110 months. Five of these patients developed a recurrent tumor. All of them had DNA type III tumors. The DNA indices showed significantly higher values in the recurrent tumor group. The 2c deviation index (DI) and the entropy value had the highest prognostic significance. No correlation to clinical follow-up was found for the AgNOR score. Based on these results, prognostic indices for paragangliomas were developed: patients with a tumor having a 2c DI exceeding 2.0, entropy value of more than 4.0. 5c exceeding rate more than 8.0, and a PCNA score more than 20.0% can be recognized as being at high-risk for developing recurrent disease.