Secretory carcinoma (SC), originally described as mammary analog secretory carcinoma, is a low-grade salivary gland tumor characterized by ETV6-NTRK3 gene fusion, identical to that in secretory carcinoma of the breast [1]. Prior to the recognition of SC as an entity, this tumor was often classified as acinic cell carcinoma, adenocarcinoma-not otherwise specified, low-grade mucoepidermoid carcinoma, or intraductal carcinoma [1], [2], [3]. Since its first description in 2010, >600 cases of SC have been reported, mostly (70 %–80 %) in the major salivary glands, with only 20 %–30 % arising from minor salivary glands [4], [5]. SCs are usually indolent in their biological behavior; although up to 25 % of cases may have locoregional lymph node metastases, they rarely metastasize distantly or undergo high-grade transformation (HGT) [6].

HGT, originally referred to as “dedifferentiated”, was first used by Dahlin and Beabout in 1971 to describe a distinct clinicopathologic entity in which low-grade chondrosarcoma was associated with, but sharply delineated from, histologically dissimilar high-grade sarcoma [7]. Since the first report of a “dedifferentiated” salivary gland acinic cell carcinoma in 1988, this rare phenomenon has been described in a variety of salivary gland carcinomas, including acinic cell carcinoma, adenoid cystic carcinoma, epithelial-myoepithelial carcinoma, polymorphous adenocarcinoma, low-grade mucoepidermoid carcinoma, and SC [8]. HGT was defined as the abrupt transformation of the conventional zone to the HGT zone without the original distinct histologic characteristics, although a transitional zone can be identified in some cases. HGT tumors are characterized by pleomorphism, prominent necrosis, a high mitotic count, and a high Ki-67 labeling index [9].

The sinonasal cavity and pharynx are the most common sites of minor salivary gland tumors of the head and neck, except for the oral cavity [10]. However, SCs in the sinonasal cavity and pharynx are rare, with only six published cases of sinonasal SC since the first cases were reported in 2015 [9], [11], [12], [13], [14], [15], and no cases of SC in the pharynx.

Here, we reanalyzed our database of minor salivary tumors from the nasal cavity, sinus, and pharynx and sought to characterize the clinical, pathologic, and molecular features of this unusual tumor, with a focus on HGT. We also carried out a review of the relevant literature.