Diagnostic and therapeutic review of cystic parathyroid lesions

Parathyroid cysts (PC) are uncommon entities in routine clinical practice. The vast majority are nonfunctioning and are commonly present as asymptomatic nodular cervical lesions. PC should be considered in the differential diagnosis of an asymptomatic neck mass. Large PC can manifest with compressive symptoms of the surrounding tissues.

The aim of this study is to describe nine new cases of PC and review the current literature regarding the clinical presentation, the aetiopathology, the diagnostic procedures, as well as the therapeutic approaches for this relatively rare clinical entity. METHODS-PATIENTS: We present nine new patients (7 females and 2 males) diagnosed with PC, which in three were ectopic. The diagnosis of PC was based on the elevated levels of PTH in the cysts fluid. Six of the patients had nonfunctioning parathyroid lesions, while the other three had functioning ones. Patients with functioning PC had elevated serum calcium and PTH levels. Five out of nine of the cases had no symptoms, while two patients had compressive symptoms and the other two had signs and symptoms of hypercalcaemia. Needle aspiration (NA) was performed in five out of six patients with nonfunctioning PC. Surgery was the treatment in all three patients with functioning PC.

Remission after NA was achieved in four out of five patients with non-functioning PC (follow-up time: 17.7±2.3 months). In two of them, two and three aspirations were needed. One patient with nonfunctioning PC submitted to surgery with no previous NA. Patients with functioning PC maintained remission after surgery (mean follow-up time: 22.1±2.9 months). In one of them, a second surgery was performed due to the co-existence of an ectopic parathyroid adenoma.

The diagnosis of a PC can be established by finding high levels of PTH in the fluid collected by the aspiration of the cyst. PTH and Ca levels in the serum can differentiate functioning from nonfunctioning PC. The treatment of choice in nonfunctioning cysts is aspiration. Surgical removal of the cyst is indicated in hyperfunctioning cysts in cases of relapse after NA in nonfunctioning cysts and when compressive symptoms are present. Based on our series, which appears to be one of the largest reported, we propose a diagnostic algorithm to guide the diagnostic and therapeutic approach to PC.