The role of the depth of invasion (DOI) in minor salivary glands tumors according to the 8th TNM classification: Pitfalls and potential misinterpretations

Abstract

• About 80-90% of minor salivary glands neoplasms are malignant. Adenoid cystic carcinoma is the most common. • In 1991 Spiro et al stated that the staging criteria and the surgical approach to MSGC was identical to that of SCC in the same locations. • The concept of DOI is not applicable to MSGCs developed in the submucosa surrounded by connective tissue or embedded in-between muscle fibers. • It would be appropriate to propose an ad hoc staging for MSGCs in order to take into account not the DOI but the potential routes of spread of the tumor.