Retroperitoneal paragangliomas: role of immunohistochemistry in the diagnosis of malignancy and in assessment of prognosis.

To present our experience of 10 patients with extra-adrenal retroperitoneal paragangliomas, and assess prognostic tests.Retrospective study of casenotes.University hospital, Italy.10 Patients who presented with paragangliomas between 1970 and 1991.Histological and immunohistochemical results, and outcome.All tumours were completely resected and there was no operative mortality. Of the 8 patients who had no metastases at presentation 3 died of recurrence 3, 5, and 10 years later, respectively; 4 were alive and free of disease 2-7 years after diagnosis. The 2 patients with synchronous bone metastases at presentation died 1 and 4 years later. Immunohistochemical analysis of type I cells (chromogranin A and neurone-specific enolase) showed little correlation with progression of disease, but there was a correlation between the presence of type II cells (S100 protein) and good prognosis.Excision is the treatment of choice for paraganglioma. Immunohistochemical techniques may provide useful information about prognosis, in particular about those patients who are at increased risk of recurrence. Long term follow up is essential, because successful management of recurrence is dependent on early recognition.