Paraganglioma of the cauda equina.

The authors present two cases of paraganglioma located in the cauda equina. Diagnosis was suspected by light microscopy and confirmed with the identification of characteristic neurosecretory vesicles. The presence of cytoplasmic filaments in both of our cases and of cilia in one case are very unusual findings in paraganglioma and seem to be characteristic of this location. The cauda equina is a extremely rare location for this type of tumor and, as far is known, only ten other cases have been reported. Paraganglioma should be considered as a diagnostic possibility in order not only to make a correct diagnosis, but also to prepare tissues for special stains and biological and electronmicroscopic studies.