Multiple Endocrine Neoplasia type 1 (MEN1) is diagnosed when two out of the three primary MEN1-associated endocrine tumors occur in a patient. Up to 10–30 % of those patients have no mutation in the MEN1 gene. It is unclear if the phenotype and course of the disease of mutation-negative patients is comparable with mutation-positive patients and if these patients have true MEN1. The present study aims to describe and compare the clinical course of MEN1 mutation-negative patients with two out of the three main MEN1 manifestations and mutation-positive patients during long-term follow-up. This is a cohort study performed using the Dutch MEN1 database, including > 90 % of the Dutch MEN1 population. A total of 293 (90.7 %) mutation-positive and 30 (9.3 %) mutation-negative MEN1 patients were included. Median age of developing the first main MEN1 manifestation was higher in mutation-negative patients (46 vs. 33 years) (P = 0.007). Mutation-negative patients did not develop a third main MEN1 manifestation in the course of follow-up compared to 48.3 % of mutation-positive patients (P < 0.001). Median survival in mutation-positive patients was estimated at 73.0 years (95 % CI, 69.5–76.5) compared to 87.0 years (95 % CI not available) in mutation-negative patients (P = 0.001). Mutation-positive and mutation-negative MEN1 patients have a different phenotype and clinical course. Mutation-negative patients develop MEN1 manifestations at higher age and have a life expectancy comparable with the general population. The apparent differences in clinical course suggest that MEN1 mutation-negative patients do not have true MEN1, but another MEN1-like syndrome or sporadic co-incidence of two neuro-endocrine tumors.

Objective: To identify the optimal surgical strategy for multiple endocrine neoplasia type 1 (MEN1)–related primary hyperparathyroidism (pHPT). To describe the course of postoperative hypoparathyroidism and to assess whether genotype is associated with persistent/recurrent pHPT. Background: Surgery is the preferred treatment in MEN1-related pHPT, but the surgical procedure of choice is still uncertain. Methods: This retrospective cohort study was performed at the Departments of Endocrinology of the University Medical Centers of Utrecht and Nijmegen, the Netherlands. Patients were selected from the Dutch MEN1 database, including all patients 16 years or older treated for MEN1 from 1990 to 2009. Data were collected by medical record review. Results: Seventy-three patients underwent parathyroid surgery. Persistent/recurrent pHPT occurred in 53% after less than 3 parathyroids resected (<SPTX), 17% after subtotal resection (SPTX), and 19% after total resection with autotransplantation (TPTX). Persistent (≥6 months) postoperative hypoparathyroidism occurred in 24% after <SPTX, 39% after SPTX, and 66% after TPTX. Median duration of hypoparathyroidism was 1.5 years, in 65% successful cessation of vitamin D/calcium was possible, even after more than 10 years. After <SPTX, patients with nonsense or frameshift mutations in exons 2, 9, and 10 had a significantly lower risk of persistent/recurrent pHPT than patients with other mutations. After SPTX/TPTX persistence/recurrence did not differ with genotype. After SPTX/TPTX persistence/recurrence was more frequent (P = 0.07) in patients without bilateral transcervical thymectomy (TCT). Conclusions: SPTX with bilateral TCT is the procedure of choice for MEN1-related pHPT. Genotype seems to affect the chance of recurrence. Postoperative hypoparathyroidism lasting 6 months or more should not be considered permanent in MEN1.

The assessment of tumor markers for diagnosing pancreatic neuroendocrine tumors (pNET) in multiple endocrine neoplasia type 1 (MEN1) patients is advised in the current guidelines but has never been validated for this purpose. The objective of the study was to assess the diagnostic accuracy of chromogranin A (CgA), pancreatic polypeptide (PP), and glucagon for pNET in MEN1. This was a diagnostic study. The study was conducted at Dutch university medical centers from 2008 to 2011, representing 90% of the total Dutch MEN1 population. Patients for whom data on tumor markers in combination with the reference standard (ie, radiological imaging) were available between 2008 and 2011 were included. The reference standard for the presence of pNET was pathology or detection on magnetic resonance imaging, computed tomography, or endoscopic ultrasound confirmed on subsequent imaging, irrespective of modality at follow-up. The area under the receiver-operating characteristic curve (AUC), positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, sensitivity, and specificity were calculated for each marker. For the analysis of PP, CgA, and glucagon, 73, 81, and 94 patients were available, respectively. The AUC for CgA was 0.48 [95% confidence interval (CI) 0.35-0.61] with a sensitivity 0.33 and a specificity 0.73; the AUC for glucagon was 0.58 (95% CI 0.46-0.70) with a sensitivity 0.43 and a specificity 0.73; and the AUC for PP was 0.64 (95% CI 0.50-0.77) with a sensitivity 0.36 and a specificity 0.74. Age, imaging modality, tumor size, and number did not influence the outcomes. The diagnostic accuracy of the tumor markers CgA, PP, and glucagon for pNET in MEN1 is low.