Sinonasal renal cell-like adenocarcinomas: robust carbonic anhydrase expression

Abstract

We report 3 new patients with sinonasal renal cell-like adenocarcinoma (SNRCLA). One case submitted in consultation demonstrated robust carbonic anhydrase IX (CA-IX) expression, leading us to a broader inquiry of CA-IX and carbonic anhydrase II (CA-II) expression in other SNRCLA, Schneiderian tissues, and histologic mimickers. Robust cytoplasmic and membranous CA-IX expression is demonstrated in 6 of 7 SNRCLAs; CA-II expression was demonstrated in 2 of 5 cases. Robust, diffuse CA-II expression is demonstrated throughout sinonasal seromucinous glands in all 10 normal Schneiderian samples. CA-IX is also expressed in all normal sinonasal samples, albeit focally. The closest salivary mimic to SNRCLA is hyalinizing salivary clear cell carcinoma; only focal CA-IX expression was demonstrated in 1 of 2 cases studied. Carbonic anhydrase expression in Schneiderian tissue speaks to its role in regulating the ion concentration of sinonasal secretions and may also explain the origin of this rare tumor.

Keywords: Adenocarcinoma; Carbonic anhydrase; Renal cell; Renal cell–like; Sinonasal.