[Malignant paraganglioma of the duodenum. Immunohistochemical and ultrastructural study of a case].

Paragangliomas of the duodenum are rare. Only 40 cases, most of them corresponding to benign tumours, have been published. In this study, we report a malignant paraganglioma of the duodenum with lymph node metastasis occurring in a 73 year old woman. The essential clinical manifestations which brought the patient to surgery were abdominal pain, melaena and anemia. The surgical specimen was investigated histologically, immunohistochemically and ultrastructurally. The tumour was composed of three types of cells: epithelial, gangliocytic and spindle shaped mesenchymal cells. The first contained ultrastructurally intracytoplasmic granules bound with double membranes; they stained with monoclonal antibodies against chromogranin. Gangliocytic cells stained with monoclonal N.S.E. antibodies and the spindle cells stained with S 100 protein. The spindle cells displayed ultrastructurally glial cell characteristics, containing micro-filaments of glial type. These immunological and ultrastructural features argued in favor of the neuroendocrine cell origin of this paraganglioma.