Gastrointestinal autonomic nerve tumor of the jejunum. Case report and review of the literature.

Gastrointestinal autonomic nerve tumor is very rare and it is difficult to distinguish this tumor from other gastrointestinal tumors due to the absence of clinical, instrumental and macroscopic features which allow pre- or intraoperative diagnosis. Our aim was to recognize the characteristic features (preoperative, intraoperative, pathological) that would allow diagnosis of gastrointestinal autonomic nerve tumor. A case of gastrointestinal autonomic nerve tumor of the jejunum is reported. Surgical specimen was routinely processed. Immunohistochemical staining was performed according to modified immunoperoxidase Avidin-Biotin-Peroxidase Complex method. An electron microscopy study was also performed. The tumor mass showed some characteristic pathological findings: histologically, it was composed of spindle cells and epithelioid cells; immunohistochemically, a focal positivity for Neuron Specific Enolase was shown, and finally, ultrastructural examination showed neuron-like cells with long cytoplasmic processes containing microtubules and bulbouns synapse-like structures with dense core neurosecretory-type granules. Preoperatively gastrointestinal autonomic nerve tumor of the jejunum must be considered and treated as a malignant tumor. A correct diagnosis is possible only with immunohistochemical and ultrastructural studies. It is probable that this tumor is more common than previously thought.