Page 136 - New epidemiological and PSMA-expression based paradigms in salivary gland tumors

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Chapter 8
Indeed, the cadaver study confirmed the presence of a defined structure containing acini and draining ducts, and the association of xerostomia and dysphagia with RT dose in the clinical cohort indicated a specific function that can be disrupted. When compared to the known major salivary glands, the tubarial glands had the most similarities with the sublingual glands based on the predominant mucous acini (hence the negative amylase staining), similar PSMA-ligand uptake, and the presence of multiple draining ducts[6,18]. It can be argued that the tubarial glands do not have a capsule as opposed to the major salivary glands, however the sublingual glands also have an unencapsulated part that consists of 8-30 minor mixed glands[19]. Additionally, the type and frequency of salivary gland tumors that occur in the nasopharynx and sublingual glands seem to be similar, with rare occurrences of benign tumors and adenoid cystic carcinoma as the most frequent malignant tumor[20–26]. As a consequence of these considerations, our interpretation of the tubarial glands could be guided by the classification that is applied to the sublingual glands, and they would qualify as a fourth pair of major salivary glands. On the other hand, the tubarial glands have many similarities with the palatal conglomerate of microscopic glands, which are classified as minor salivary glands. Based on the overlapping spectrum of their characteristics it could be argued that all salivary glands together could be interpreted as a continuum, formed by smaller and larger collections of acini that together form a salivary gland system. In this approach, the tubarial glands should not be classified as separate organs or as minor or major salivary glands, and can better be interpreted as macroscopic parts of the composite salivary gland organ system.
Regardless of the classification of the tubarial glands as either a conglomerate of minor glands, a major gland, a separate organ, or as a new part of an organ system, the tubarial glands are macroscopic glandular tissue locations with clinical relevance. Therefore, they require a name that allows unique identification in daily clinical practice. The proposed name tubarial glands is based on their anatomical location, in coherence with the naming strategy for the other macroscopic salivary glands (parotid, submandibular, sublingual). This also prevents confusion with the microscopic tubal glands lining the auditory tube. Other names that were considered included Eustachian or Rosenmüllers’ glands, but these did not optimally match the anatomical location, and eponymous medical nomenclature is no longer considered desirable.