Zenker diverticulum in the right side of the neck resembling a thyroid mass at ultrasound

Zenker's diverticulum represents the most common form of pharyngo-oesophageal diverticula usually occurring on the left side of the neck. Due to its anatomical proximity to the thyroid, it can mimic a thyroid mass. Here we describe the case of an asymptomatic 49-year-old man referred to the Thyroid Clinic of the Policlinico Umberto I Hospital-"Sapienza" University of Rome for thyroid sonography due to a family history of autoimmune thyroid disease. The patient's thyroid blood tests did not reveal any abnormalities. The sonographic examination showed a dishomogeneus and hypoechoic thyroid gland. In addition, in the third middle of the right lobe, a mass (with a diameter greater than 26 mm), with heterogeneous internal echogenicity, hypoechoic margins and internal hyperechoic spots was recorded, with no appreciable flow at the Doppler evaluation. The TI-RADS score was 4c. Hence, the patient underwent ultrasound-guided fine-needle aspiration cytology that revealed the presence of squamous cells without cytological atypia, erythrocytes, muscular and vegetable fibres, colonies of bacteria in the absence of inflammatory infiltrate. This was consistent with the diagnostic hypothesis of oesophagus diverticulum, which was confirmed by means of a barium-swallow oesophagography. This case report underlines the possibility that a suspicious thyroid mass may result from a Zenker's diverticulum, even if located on the right side, especially if the lesion has a heterogeneous echo-texture, a hypoechoic rim and internal hyperechoic spots.