Parathyroid allotransplantation for severe post-surgical hypoparathyroidism: a Brazilian experience

Abstract

Purpose Parathyroid allotransplantation is an alternative therapy for refractory permanent hypoparathyroidism (PH). Herein, we present the cases of two women who developed severe PH after neck surgery for papillary thyroid cancer and underwent parathyroid allotransplantation. Despite taking high doses of calcium and calcitriol supplements, the patients experienced persistent and severe hypocalcemic symptoms. Methods Fresh parathyroid tissue was removed and prepared from two patients with hyperparathyroidism secondary to end-stage kidney disease, and implanted in the non-dominant forearm of the recipients. Donors and recipients were ABO-compatible, and immunological screening was performed only in Case 2 (HLA typing, Panel Reactive Antibody, and crossmatch tests). A short-term immunosuppressive regimen was adopted, which consists of three days of methylprednisolone followed by seven days of prednisone. Results In Case 1, oral supplementation decreased to half of the initial dose one month after transplantation and to one-fifth at the end of a 12-month follow-up period. In Case 2, intravenous calcium could be discontinued one week post-transplantation, and it was not required until six months after transplantation. Serum parathyroid hormone levels did not increase and remained mostly undetectable in both cases. In contrast, serum calcium levels increased significantly, and both patients experienced relief from hypocalcemic symptoms. Conclusion Parathyroid allotransplantation can be an effective and safe treatment for permanent PH, and should be considered in severe cases. Nevertheless, formal recommendations depend on additional studies and validated protocols.