I read with interest the article entitled “Adenocarcinoma of the anterior tongue: A case report” by Gehani et al. . In this article, the authors presented an unusual case of adenocarcinoma arising from the anterior ventral tongue in a 74-year-old man. In their literature review concerning adenocarcinoma arising from the anterior two-thirds of the tongue, the authors identified only 3 cases, including a papillary adenocarcinoma , a tubular adenocarcinoma , and a polymorphous low-grade adenocarcinoma . In this report, the authors diagnosed their case just as adenocarcinoma. I am puzzled that whether they mean their case as adenocarcinoma not otherwise specified or not.

Salivary gland carcinoma is a rare and very heterogeneous disease. The latest WHO salivary gland tumor classification in 2005 covers 24 histological types, most of which, such as adenoid cystic carcinoma, and mucoepidermoid carcinoma, are adenocarcinomas . A group of salivary gland carcinomas with ductal or glandular differentiation that fail to meet the diagnostic criteria for any other specific type is termed adenocarcinoma not otherwise specified, and the qualifier “not otherwise specified” should be included . However, in some literatures, adenocarcinoma not otherwise specified has often been reported simply as adenocarcinoma .

If the authors mean their case as adenocarcinoma not otherwise specified, it is confusing that all three cases in their literature review were not adenocarcinoma not otherwise specified. Polymorphous low-grade adenocarcinoma is a clinically and pathologically different entity from adenocarcinoma not otherwise specified, as the authors pointed out. There is no papillary adenocarcinoma or tubular adenocarcinoma in the list of the latest WHO salivary gland tumor classification, and the two cases of adenocarcinoma located on the anterior tongue named as “papillary carcinoma of minor salivary gland” and “tubular adenocarcinoma” were considered to be bona fide cribriform adenocarcinoma of minor salivary gland , a newly characterized salivary gland tumor.

If the authors only mean their case as adenocarcinoma, namely, a malignant tumor derived from glandular tissue or in which the tumor cells form recognizable glandular structures, it should be noted that most of salivary carcinomas, such as adenoid cystic carcinoma, and mucoepidermoid carcinoma, are adenocarcinomas. To my knowledge, other types of salivary gland adenocarcinomas, such as adenoid cystic carcinoma , papillary cystadenocarcinoma , and mucoepidermoid carcinoma have also been reported in this anatomic location. Furthermore, adenocarcinoma is often a preliminary diagnosis and should be further clarified, because of different malignant potential and prognosis of salivary gland carcinomas.