[Congenital cysts and fistulae of the face and the neck]. / Kystes et fistules congénitaux de la face et du cou.

The authors review the embryological, clinical and therapeutic aspects of congenital facial and cervical cysts (C) and fistulae (F), based on a personal series of 85 cases (facial: 18, latero-cervical: 29, mediocervical: 38) observed during a 5-year period. The facial forms are the result of an incomplete coalescence of the facial buds and most often present as helical F (17/18). Laterocervical C and F are due to abnormal evolution of branchial clefts; the main clinical forms are related to anomalies of the 2nd branchial cleft (24/29), usually presenting as sinus localized at the anterior border of the lower third of the sternocleidomastoid muscle (8) and amygdaloid cysts. Thyroglossal duct cysts are the most frequent of the medio-cervical C and F (35/38); they usually present as a mediocervical cyst in the thyro-hyoid space which may be revealed by an infection or a fistulization. The only appropriate treatment of congenital facial and cervical C and F is surgery providing that the resection is meticulous with complete resection of the fistula in order to avoid relapse. Complete resection also suppresses the risk of secondary malignant degeneration of amygdaloid and thyroglossal duct cysts.

Anatomical reconstruction of the thyroglossal duct.

The high postoperative recurrence rate of the thyroglossal duct cyst is well known. Since Sistrunk's operation was used, the recurrence rate was remarkably reduced, but the anatomical description of the thyroglossal duct through the entire tract has not been clarified in detail. For a more accurate anatomical understanding of the thyroglossal duct, 10 specimens obtained from Sistrunk's operation were studied using histological reconstruction, and a common running pattern of the thyroglossal duct was found. The cyst is usually located caudal to the hyoid bone mostly at the midline. The duct extends upward from the cyst ventral to the hyoid bone, with many or a few branches and secretory glands. These ducts or branches merge into a single duct at the level of the cranial portion of the hyoid bone. However, as it leaves the hyoid bone and approaches the foramen cecum, a single duct spreads out into many ductuli like the tip of a broom, which communicate with many secretory glands. There were three cases in which the duct was found behind the hyoid bone, but in no case did the thyroglossal duct run through the back of the hyoid bone. The duct behind the hyoid bone was recognized as a branch from the main duct in the dorsal direction. It ascended to the dorsal surface of the hyoid bone and terminated blind. These findings emphasized the importance of Sistrunk's operation to prevent a recurrence.