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Differences between sporadic and MEN related primary hyperparathyroidism

Primary hyperparathyroidism ( PHPT ) is most commonly sporadic ( sPHPT ). However, sometimes PHPT develops as part of multiple endocrine neoplasia ( MEN ) type 1 or 2A.
In all, parathyroidectomy is the only curative treatment. Nevertheless, there are important differences in clinical expression and treatment.

Researchers have analyzed a consecutive cohort of patients treated for sporadic, MEN1-related, and MEN2A-related PHPT and compared them regarding clinical and biochemical parameters, differences in preoperative workup, operative strategies, findings, and outcome.

A total of 467 patients with sporadic primary hyperparathyroidism, 52 with MEN1- and 16 with MEN2A-related primary hyperparathyroidism were analyzed.
Patients with sporadic primary hyperparathyroidism were older, more often female and had higher preoperative calcium and parathyroid hormone levels, when compared with MEN1 and MEN2A patients.

Minimally invasive parathyroidectomy ( MIP ) was performed in 367 of 467 sPHPT patients ( 79% ). One abnormal parathyroid was found in 426 patients ( 91% ); two or more in 35 patients ( 7% ). In six patients ( 1% ) no abnormal parathyroid gland was retrieved.

Of 52 MEN1 patients, eight ( 15% ) underwent a MIP and 44 patients ( 85% ) underwent conventional neck exploration ( CNE ); with resection of fewer than 3½ enlarged glands in 21 patients ( 40% ), subtotal parathyroidectomy ( SPTX, 3-3½ glands ) in seventeen ( 33% ) and total parathyroidectomy with autotransplantation ( TPTX ) in six ( 12% ).
Eleven patients ( 21% ) had persistent disease, 29 ( 56% ) recurrent primary hyperparathyroidism and nine ( 17% ) permanent hypoparathyroidism, mostly after TPTX.

Of 16 MEN2A patients, six ( 38% ) underwent minimally invasive parathyroidectomy, four ( 25% ) conventional neck exploration and six ( 38% ) selective resection of the enlarged gland(s) during total thyroidectomy.
Three patients ( 19% ) suffered from persistent primary hyperparathyroidism and two ( 13% ) developed recurrent disease.

In conclusion, sporadic PHPT, MEN1- and MEN2A-related primary hyperparathyroidism are three distinct entities as is reflected preoperatively by differences in gender, age at diagnosis and calcium and PTH levels.
MEN2A patients are very similar to sporadic primary hyperparathyroidism with respect to operative approach and findings. Minimally invasive parathyroidectomy is the treatment of choice for both. MIP has low rates of persistent and recurrent primary hyperparathyroidism and a low complication rate.
The percentage of multiglandular disease and recurrences are significantly higher in MEN1 patients, demonstrating the need for a different approach. Researchers advocate treating these patients with conventional neck exploration and subtotal parathyroidectomy. ( Xagena )

Twigt BA et al, Orphanet Journal of Rare Diseases 2013, 8:50 doi:10.1186/1750-1172-8-50