Salivary gland heterotopia in the lower part of the neck.
Heterotopic salivary gland tissue in branchial cleft cysts in the upper part of the neck reputedly differentiates from the epithelial lining of the cyst. We describe a patient with salivary gland tissue found in the lower part of the neck. How salivary gland tissue finds its way to the lower neck is obscure. It is conceivable that the tissue originated from a precervical sinus or cervical vesicle, a distinct embryologic structure that forms in the lower part of the neck between the second branchial arch and the upper thoracic wall, but that normally disappears by the time of birth. The epithelial lining of the cervical vesicle is thought to be associated with the early development of the glossopharyngeal and vagus nerves. Salivary gland tissue may differentiate from the epithelial lining of cervical vesicles and nurture the growing nerves by nerve growth factor elaboration.