Intestinal-type sinonasal adenocarcinomas. Immunohistochemical profile of 66 cases.

INTRODUCTION AND OBJECTIVES Intestinal-type sinonasal adenocarcinomas are malignant epithelial tumours. Around 8-25% of all sinonasal malignant tumours are intestinal-type adenocarcinomas, which are related to wood dust exposure. Four histological subtypes have been described: papillary, colonic, solid and mucinous. We performed a pathological and immunohistochemical study in order to describe characteristics with prognostic, diagnostic and therapeutic value, and also to compare our results with previous studies. METHODS Sixty six tumour samples were analysed and protein expression of p53, p16, E-cadherin, β-catenin, epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2/neu) and cyclooxygenase-2 (COX-2) was performed by tissue microarray blocks. RESULTS The 63% of cases were p53 positive; 37% showed nuclear staining with β-catenin and 100% with E-cadherin, while 98% showed membrane staining with β-catenin, 7% with EGFR, 8% with HER2/neu and 52% with COX-2; and 59% of the cases lost p16 expression. CONCLUSIONS Intracranial invasion was the worst prognostic associated event. Solid and mucinous tumours were the most aggressive histological subtypes. Intracranial invasion was more frequent in mucinous subtype tumours. Immunohistochemical results were similar in all tumour subtypes, except for mucinous tumours, which showed weak expression of E-cadherin and β-catenin. Comparing with previous studies, we found a lower expression of EGFR, HER2/neu and COX-2. The p16 expression was associated with worse survival and metastatic disease.