Carcinoma ex Pleomorphic Adenoma of the Nasal Cavity

Background: Carcinoma ex pleomorphic adenoma (CXPA) is a malignant epithelial neoplasm arising in a benign mixed tumor (i. e., pleomorphic adenoma or PA); it accounts for approximately 3-4% of all salivary gland neoplasms. CXPA is exceedingly rare in the nasal cavity, with only three cases previously documented. Methods: We report two cases of women presenting with masses of the nasal cavity. The tumors were resected and evaluated grossly and by routine microscopy. Results: Both patients presented with nasal obstruction, and one patient reported epistaxis. Grossly, the tumors were 2.5 and 3 cm in greatest dimension, respectively. In each case, microscopic examination of the tumor revealed an infiltrating carcinoma arising in association with foci of benign PA. The carcinoma types were adenoid cystic carcinoma and high grade adenocarcinoma, not otherwise specified. Both cases were widely (i. e., >1.5 mm) invasive beyond the preexisting PA. The findings were diagnostic of CXPA. Conclusions: Carcinomatous transformation of a PA in the nasal cavity is extremely rare, but does occur. Accordingly, PAs of this site should be thoroughly sampled and closely examined to exclude the possibility of malignant transformation.