CYTOKERATIN EXPRESSION IN ADRENAL PHEOCHROMOCYTOMAS AND EXTRAADRENAL PARAGANGLIOMAS

Aim-To examine whether adrenal phaeochromocytomas and extra-adrenal pa ragangliomas are immunoreactive for commercially available and routine ly used cytokeratin antibodies. Methods-18 extra-adrenal paraganglioma s and seven adrenal phaeochromocytomas were stained with CAM 5.2, AE1/ 3, and 34 beta E12 following microwave antigen retrieval of formalin f ixed tissue. Results-A single case from the cauda equina was positive for both CAM 5.2 and AE1/3. In addition, two other cases-an intravagal and an orbital paraganglioma-also showed strong immunopositivity with CAM 5.2 and AE1/3. All phaeochromocytomas were negative with all epit helial markers. Conclusions-Cauda equina paragangliomas are known to s tain with cytokeratins; however, occasional paragangliomas from other sites may also be immunoreactive with cytokeratins. If the results of immunohistochemistry are not interpreted in the clinical and morpholog ical context, the failure to recognise that extra-adrenal paragangliom as may on occasion react with anticytokeratin antibodies may lead to t heir being confused with metastatic carcinomas.