Parathyroid cysts are rare, representing 1% of all neck swellings. A correct preoperative diagnosis is rarely formulated, especially because of the non-specific clinical and ultrasonographic findings; for this reason, patients are often submitted to surgery for thyroid nodules. In the present report we describe a case where the preoperative diagnosis was correctly formulated following the aspiration and PTH assay of clear, colorless, watery fluid from the cyst. While cyst aspiration is considered the elective treatment for these lesions, recurrences being uncommon, surgery was indicated in the present case because of two recurrences after aspiration and the onset of compressive symptoms. Cystic masses of the neck should be accurately diagnosed to recognize their true nature and to allow their correct and non-invasive treatment: surgery is indicated only when recurrences and symptoms are present. Indications for aspiration of all solitary cysts of the neck should be considered to correctly identify their nature.