Four Cases of Esophageal Diverticulum Presented as Incidentally Discovered Asymptomatic Posterior Thyroid Nodules

Abstract

Abstract Esophageal content in the thyroid by fine-needle aspiration is a rare occurrence. Here are four cases of esophageal diverticulum that presented as incidentally discovered asymptomatic posterior thyroid nodules in four patients (one 85-year-old female, one 85-year-old male, one 57-year-old male, and one 26-year-old female) who underwent ultrasound-guided fine-needle aspiration (FNA). The FNA cytopathological findings include bland mature nonkeratinizing superficial squamous cells, abundant filamentous bacteria, scattered degenerated chronic inflammatory cells, and amorphous debris, consistent with oral pharyngeal contents. These findings in the thyroid FNA biopsy may raise differential diagnoses, including Zenker diverticulum and Killian-Jamieson diverticulum of the esophagus, thyroglossal duct fistula and a third or fourth branchial fistula, and benign epidermal inclusion cyst. Thyroglossal duct fistula appears as a midline tract, which may connect the thyroid gland and the foramen cecum, as well as the branchial fistula usually present in the pediatric population, and it may connect the thyroid gland and the hypopharyngeal piriform sinus, although with an unusual presentation seen in adults. However, all four cases were reviewed with radiologists and confirmed as deep posterior thyroid nodules. The squamous epidermal inclusion cyst is usually in the superficial dermis and has predominantly anucleated squamous cells and very few if any well-preserved nucleated squamous cells. The abundant filamentous bacteria/yeast may represent colonization and no infection, which is confirmed by almost absence of neutrophils. So, the final diagnosis of these four cases is suggestive of esophageal diverticulum and no surgical treatment is necessary with the recommendation of esophagogastroduodenoscopy. As noted above, there is no evidence of malignancy; however, the false-negative rate of FNA diagnosis in a squamous-related entity is reported to be about 2% to 5%, so these patients are deemed appropriate for follow-up. In summary, we presented four cases of incidentally discovered asymptomatic posterior thyroid nodules suggestive of esophageal diverticulum by FNA biopsy.