A CASE OF PARATHYROID CYST INITIALLY SUSPECTED AS A LATERAL CERVICAL CYST

Abstract

　The differential diagnosis of lateral cervical cystic disease is wide, including lateral cervical cyst, ranula, lymphangioma, cutaneous cyst, lymphadenopathy, etc, and medical examinations and tests must be carried out bearing these diagnoses in mind before surgery. We encountered the case of a patient who was suspected preoperatively as having a lateral cervical cyst, but was diagnosed after surgery as having a parathyroid cyst. Parathyroid cyst is a relatively rare disease and could be functioning or non-functioning. Functioning parathyroid cysts cause hyperparathyroidism, associated with high plasma levels of parathormone (PTH) and calcium (Ca). Non-functioning parathyroid cyst is associated with normal parathyroid function and normal serum PTH and Ca levels. In this patient, we diagnosed a non-functioning parathyroid cyst based on the findings of blood and histopathological examinations. Some lateral cervical cystic diseases such as lymph node metastasis and symptomatic functioning parathyroid cyst need early diagnosis and treatment, but it is sometimes difficult to diagnose lateral cervical cystic disease only from cytologic and imaging examinations. The purpose of this report is to call attention to the need for inclusion of parathyroid cyst in the differential diagnoses of lateral cervical cysts, and suggest avoid missing malignant or fatal disease. We believe that histopathological examination should be prioritized if preoperative diagnosis is difficult.