Multiple endocrine neoplasia type 1 (MEN1) is a hereditary syndrome characterized by a mutation in the MEN1 gene located at chromosome 11q13. This syndrome has an autosomal dominant pattern of inheritance. The MEN1 gene encodes a 610 amino acid protein, menin, which is deeply involved in transcriptional regulation.1 The clinical characteristics of MEN1 include the development of multiple tumors in different endocrine glands: parathyroid asymmetric hyperplasia, entero-pancreatic endocrine tumors and pituitary tumors.2
Primary hyperparathyroidism (PHPT) will be present in > 95% of patients with MEN1 diagnosis, and it is the initial manifestation in 60–90% of patients.3 The classic clinic manifestations of PHPT include fatigue, constipation bone pain, depression, nephrolithiasis among others. It is well known that in recent years PHPT presents as an asymptomatic entity in the majority of cases, this is because it is detected on routine laboratory work as isolated hypercalcemia.4
Parathyroidectomy is the treatment of choice for MEN1 associated PHPT.5 As mentioned before, multiple gland involvement is the responsible for this condition in MEN1 patients, contributing to high risk of persistent or recurrent PHPT. The surgical treatment for MEN1 associated PHPT recommended is open bilateral neck exploration. There are different strategies to achieve optimal results: less than subtotal parathyroidectomy, subtotal parathyroidectomy or total parathyroidectomy with autotransplantation. The main goals when treating this group of patients are to obtain normocalcemia, decrease the incidence of permanent hypoparathyroidism and decrease the number of operations that the patient will need. In order to achieve optimal results it is critical to choose the best surgical strategy.6
When the results among different surgical strategies are compared, subtotal and total parathyroidectomy with autotransplantation result in durable control of MEN1 associated PHPT and have longer recurrence free periods in comparison with more conservative resections. On the other hand, total parathyroidectomy with autotransplantation has a higher incidence of severe hypoparathyroidism compared with subtotal parathyroidectomy.7 For this reason and according to the most recent Clinical Practice Guidelines for MEN1 subtotal parathyroidectomy is suggested as the initial management of PHPT in MEN1, but total parathyroidectomy with autotransplantation may also be considered in some cases, like patients with extensive disease either at first or at repeat surgery.3
Recurrent MEN1 associated PHPT is diagnosed in 33 to 35% after initial operation, with higher recurrence rate in less than subtotal parathyroidectomy (46 to 50%) and lower recurrence rate in total parathyroidectomy and autotransplantation (6 to 35%). Reoperation of recurrent MEN1 associated PHPT is recommended when associated symptoms or complications are present.8–11
In the reoperation scenario the goals are the same as those established for the index operation, specifically obtain normocalcemia and decrease the incidence of permanent hypoparathyroidism. Autograft debulking in patients with recurrent MEN1 associated PHPT who were initially treated by total parathyroidectomy and autotransplantation is not a frequently practiced procedure. The balance between autograft debulking extension and permanent hypoparathyroidism should be pursued and the implementation of a well-established technique could be helpful. For this reason, we started using the Miami criteria to intraoperative assessment of adequate tissue debulking. These criteria were described to predict operative success during minimally invasive parathyroidectomy.