Evaluation of the expression and significance of Claudin-5 and CD99 in solid-pseudopapillary neoplasms and neuroendocrine tumors of pancreas / 中华病理学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the expression of endothelium tight junction protein Claudin-5 and intercellular adhesion molecule CD99 in solid-pseudopapillary neoplasms (SPN) and neuroendocrine tumors of pancreas (P-NET), and their significance in the differential diagnoses.</p><p><b>METHODS</b>Immunohistochemical staining of Claudin-5 and CD99 was performed in 37 cases SPN and 21 cases of P-NET.</p><p><b>RESULTS</b>Membranous Claudin-5 expression was observed in all cases of SPN but was absent in all cases of P-NET. The difference was significant (P < 0.01). In SPN, 91.9% (34/37) of the cases displayed paranuclear dot-like immunoreactivity for CD99; in contrast, 61.9% (13/21) of the cases of P-NET displayed membranous staining (P < 0.01). There was a positive association between the expression of Claudin-5 and CD99 in SPN (r = 0.421,P = 0.001).</p><p><b>CONCLUSIONS</b>Although the macroscopic and microscopic features of SPN are quite characteristic, they may not allow confident differentiation from P-NET in all cases, especially when these characteristics are not classical. If necessary, immunostaining for Claudin-5 and CD99 can help to differentiate between these entities.</p>