Parathyroid cysts are infrequent lesions of which most are non-functional. They are often misdiagnosed as thyroid cysts. Pre-operative diagnosis and differentiation from thyroid cysts is generally difficult. We hereby report a case that was admitted to the emergency room and was diagnosed as hypercalcemic crisis. The mass found during the neck examination was thought to be a thyroid nodule. A right total and left subtotal thyroidectomy was performed. Palpable thyroid nodule was diagnosed as cystic parathyroid adenoma postoperatively. When a cystic lesion is found in the neck of a patient, a pararthyroid cyst should be considered.