Tumour detection and outcomes of surveillance screening in SDHB and SDHD pathogenic variant carriers.

OBJECTIVE: Succinate dehydrogenase subunit (SDHx) pathogenic variants predispose to phaeochromocytoma and paraganglioma (PPGL). Lifelong surveillance is recommended for all patients to enable prompt detection and treatment. There is currently limited evidence for optimal surveillance strategies in hereditary PPGL. We aim to detail the clinical presentation of PPGL in our cohort of non-index SDHB and SDHD pathogenic variant carriers. METHODS: Retrospective analysis of medical and genetic records from a single tertiary referral centre identified SDHB or SDHD pathogenic variants in 74 non-index cases (56 SDHB and 18 SDHD). Surveillance screening for asymptomatic relatives consisted of annual plasma metanephrine measurement and whole-body MRI with contrast at 3-5 yearly intervals. RESULTS: Twenty-three out of 74 non-index patients (10 SDHB and 13 SDHD) were diagnosed with PPGL, 17 patients through surveillance screening (24 tumours in total) and 6 diagnosed prior to commencement of cascade screening with symptomatic presentation. MRI with contrast identified PPGL in 22/24 screen-detected tumours and 5/24 tumours had elevated plasma metanephrine levels. Penetrance in non-index family members was 15.2 and 47.2% for SDHB carriers and 71.6 and 78.7% for SDHD carriers at age of 50 and 70 years, respectively. CONCLUSION: Surveillance screening with combined biochemical testing and imaging enables early detection of PPGL in asymptomatic relatives with SDHx pathogenic variants. The presence of disease at first screen was significant in our cohort and hence further multi-centre long-term data are needed to inform counselling of family members undergoing lifelong surveillance.

Subtotal parathyroidectomy as an adequate treatment for primary hyperparathyroidism in multiple endocrine neoplasia type 1.

HYPOTHESIS: The most appropriate surgical approach for hyperparathyroidism (HPT) in multiple endocrine neoplasia type 1 remains controversial. It has been advocated that reoperations for recurrent disease are easier to perform after total parathyroidectomy (TP) with autotransplantation than after subtotal parathyroidectomy (SP). In view of our large experience in patients with secondary HPT for whom TP with autotransplantation did not simplify reoperations, SP remains our preferred treatment for patients with HPT and multiple endocrine neoplasia type 1. DESIGN: Retrospective cohort study. SETTING: Tertiary referral medical center. PATIENTS: A total of 29 consecutive patients (22 women, 7 men; mean age, 42.2 years) with multiple endocrine neoplasia type 1 who underwent definitive cervical exploration for HPT. MAIN OUTCOME MEASURES: Temporary and permanent hypocalcemia, pattern of parathyroid disease, and sites and timing of recurrent HPT. Definitive primary surgery included SP in 21 patients, TP with autotransplantation in 4 patients, and less-than-subtotal parathyroidectomy in 4 selected patients. RESULTS: The mean follow-up was 88.5 months (range, 8-285 months). Four patients died during follow-up; 2 of these deaths were related to multiple endocrine neoplasia. No patients had persistent HPT. Temporary hypocalcemia occurred in 12 SP cases (57%), 4 TP with autotransplantation cases (100%), and 0 less-than-subtotal parathyroidectomy cases. Permanent hypocalcemia requiring long-term treatment occurred in 2 SP cases (10%), 1 TP with autotransplantation case (25%), and 0 less-than-subtotal parathyroidectomy cases. Four patients developed recurrent disease, including 1 with SP, 2 with TP with autotransplantation, and 1 with less-than-subtotal parathyroidectomy at 57 months, 197 and 180 months, and 164 months, respectively, representing 14% of all of the patients and 43% of patients with more than 10 years of follow-up. CONCLUSIONS: Recurrent HPT occurs many years after definitive primary surgery (median, 14.3 years). Surgical treatment should therefore aim to minimize the risk of permanent hypocalcemia and facilitate future surgery. When correctly performed, SP fulfills these objectives.

Negative preoperative localization studies are highly predictive of multiglandular disease in sporadic primary hyperparathyroidism.

BACKGROUND: The development of localization studies and quick parathyroid hormone assay (QPTH) has allowed the development of focused surgery in sporadic primary hyperparathyroidism. The aim of this investigation was to determine whether localization studies select a specific population of patients. METHODS: From 1999 to 2001, 213 patients underwent surgery for sporadic primary hyperparathyroidism. All were investigated with sestamibi scanning and ultrasonography. When at least 1 study showed a positive result (n=175), the patient underwent a video-assisted approach with QPTH. When results were negative (n=38), the patient underwent cervicotomy and exploratory procedures of all 4 parathyroid glands. RESULTS: All patients are cured (mean follow-up, 17.8+/-10.3 months [SD]). Patients with negative preoperative study results had a high risk of multiglandular disease (12/38 patients; 31,6%), compared with patients with 1 positive study result (3/83 patients; 3.6%; P<.0001) and those with 2 concordant positive study results (0/92 patients; P<.0001). CONCLUSION: When preoperative localization study results are negative, the patient has a high risk of multiglandular disease, and a conventional cervicotomy with identification of the 4 glands is recommended strongly. When only 1 localization study is positive, the risk of multiglandular disease justifies the use of QPTH during a focused approach. When positive localization study results are concordant, the use of QPTH is questionable during a focused approach.

Primary hyperparathyroidism in MEN 1--how radical should surgery be?

Primary hyperparathyroidism is the most common manifestation of MEN 1 syndrome. The management of these patients is complex due to the underlying disease process, which predisposes patients to persistent and recurrent disease. The surgical treatment of patients with MEN 1 and hyperparathyroidism can therefore be considered to be palliative in nature. The basic principles of surgery include (1) obtaining and maintaining normocalcaemia for the longest time possible, avoiding persistent/recurrent hypercalcaemia, (2) avoiding surgically induced hypocalcaemia, and (3) facilitating future surgery for recurrent disease. Two approaches have been described as the best practice for patients with hyperparathyroidism in MEN 1: subtotal parathyroidectomy, leaving a remnant of no more than 60 mg in the neck, and total parathyroidectomy with immediate autotransplantation of 10-20 1 mm(3) pieces of parathyroid tissue. Both approaches should be combined with efforts to exclude supernumerary glands and ectopic parathyroid tissue by including resection of fatty tissue from the central neck compartment and thymectomy in all patients. Cryopreservation of parathyroid tissue should be performed whenever facilities are available. In patients with persistent or recurrent disease, an attempt to obtain total elimination of cervical parathyroid tissue is justified, combined with cryopreservation of parathyroid tissue. As radical as surgery is for hyperparathyroidism in MEN 1, the surgeon must take steps to avoid permanent hypoparathyroidism, which in young patients may be worse than the disease itself.