Sinonasal renal cell-like adenocarcinoma with EGFR overexpression of the maxillary sinus: Report of a high-grade case and a review of the literature

Abstract

Sinonasal renal cell-like adenocarcinoma (SRCLA), which is an extremely rare but established entity, belongs to the non-salivary gland type of low-grade adenocarcinomas arising from the sinonasal tract. We report a case of high-grade SRCLA. The patient was a 63-year-old Japanese male, who complained of nasal obstruction. Histologically, the tumor exhibited solid nests and sheet-like structures composed of atypical clear or eosinophilic cells with central necrosis. The tumor cells contained periodic acid Schiff-positive glycogen. Immunohistochemically, they were positive for cytokeratin (CK)7, CD10, carbonic anhydrase (CA)-IX, the epidermal growth factor receptor (EGFR), mucin 1, and cancer antigen 125, whereas they were negative for CK20, caudal type homeobox 2, CK5/6, p40, vimentin, S-100, a renal cell carcinoma marker, paired box gene 8, and the human epidermal growth factor receptor 2. Both local recurrence and late lymph node metastases arose in this case. Therefore, the tumor was considered to be clinically aggressive and was diagnosed as a high-grade SRCLA. Immunostaining of CD10 and CA-IX was very diagnostically useful. Although 14 cases of SRCLA have been reported previously, all of them involved low-grade malignancies, and no descriptions of their EGFR statuses were provided. This is the first report about a high-grade SRCLA exhibiting EGFR overexpression.