Salivary heterotopia may occur in 3 forms: as accessory salivary glands, in association with branchial cleft anomaly or as a heterotopic salivary gland tissue (HSGT) (1). Accessory salivary glands are localized close to the major glands and have a duct that connects to the main salivary duct, most frequently they are associated with Parotid gland and Stenson duct, with the prevalence up to 25% of the population (1). Branchial cleft anomalies, due to their embryological origin, contain tissue that may differentiate into salivary gland tissue (1). In contrast, true heterotopic salivary gland tissue (HSGT) is defined as presence of a normal salivary tissue outside of the major, minor, or accessory salivary glands, together with exclusion of clinical and histopathological features characteristic for branchial cleft anomalies (1-3). They present as masses, cysts or draining sinuses (4) and may be classified by its location into intranodal, most commonly in periparotid lymph nodes (2, 3) or extranodal, typically occurring in the lower neck region, along the anterior border of the sternocleidomastoid muscle (5). However, numerous other locations have been reported including mandible, parathyroid glands (6), larynx (so far 5 cases in English literature) (7, 8), middle ear (9), gastrointestinal tract (10, 11) cheeks (12). True HSGT is a rare condition. Out of 119 patients with lateral neck anomalies treated in the University Department of Otolaryngology in Madrid, Spain in the period of 12 years in 10 patients salivary gland tissue was identified, but only 5 accomplished criteria for HSGT (13).

Most lesions are diagnosed within the first months of life or in the early childhood. Typical clinical manifestation is a draining sinus, painless swelling or enlarged nodule, located unilaterally on the right side of the lower parts of the neck, often accompanied by intermittent draining of a clear, saliva-like fluid, connected with meal consumption (5, 13). Occasionally, ectopic salivary glands can appear bilaterally, and those patients often have family history of cervical anomalies (14). Interestingly, Hsu et al. reported a case of familial ectopic salivary gland which persisted through five generations – the pedigree of the propositus indicated an autosomal dominant pattern of inheritance (15).

The pathogenesis of these remains uncertain. There are several concepts, but the one that appears the most widely accepted is that some elements of the branchial arches become displaced during the embryologic development and an ectopic ectomesenchyme induces the development of a heterotopic salivary gland- type tissue (1). Other theories include abnormal differentiation of local tissue, dislocation of a portion of one of the normal salivary glands, inclusion of salivary tissue in lymph nodes, and abnormal migration of normal salivary tissue (1).

Below we would like to present an example of an unusual location of ectopic salivary glands within the oral cavity that was observed in our clinic.