Immunohistochemical expression patterns of S100, synaptophysin, chromogranin A and neuron specific enolase in predicting malignant behaviour in paragangliomas

Abstract

PURPOSE: The purpose of this study was to evaluate the role of immunohistochemical markers in the prediction of malignancy in paragangliomas. METHODS: Our institute's patient records between 1990-2012 were retrieved in order to identify patients who were treated for paragangliomas. Size and location of the tumour, existence of concurrent metastatic disease, patient demographics and survival were recorded. Haematoxylin-eosin stained slides were reviewed and all tumours were stained specifically for neuron specific enolase (NSE), chromogranin, synaptophysin and S100 protein positivity. Positivity and expression patterns of the above markers were evaluated and compared between malignant and benign tumours. Malignant behaviour was defined when patient had concurrent or subsequent lymph node involvement, local recurrence and/or metastases. RESULTS: A total of 22 patients with a diagnosis of paraganglioma were treated in our institutes. Female to male ratio was 1.75: 1. The mean age was 43.5 and 51.6 years for women and men, respectively. In 5 patients the tumors had malignant clinical behavior. Their mean size was 3.65 cm for benign and 4.56 cm for malignant neoplasms. NSE expression was diffuse in 47.1% and 0% for benign and malignant tumors, respectively (p=0.10). S100 expression in the periphery of the tumour was typical in 88.2% and 0% for benign and malignant tumors, respectively (p<0.001). CONCLUSION: Immunohistochemical profile from the combination of NSE, synaptophysin chromogranin and S100 staining patterns can serve as a cheap and valuable tool for correctly distinguishing between malignant and benign paragangliomas with high diagnostic accuracy.