Endocrine Abstracts

A 60-year lady with a history of thyroidectomy for medullary thyroid presented for her regular follow-up - first presentation in our clinic in Nov 2020 (previous visits to another endocrinology clinic).

History: 2005: uretheroplasty for left uretheral hypoplasia January 2017: thyroid ultrasound: a unique left lobe thyroid nodule (1 cm)- basal calcitonin x3 UNL (nr <11.5) and 94 pg/ml calcium stimulated CTN; RET gene - negative for mutations in exons 8/10/11/13/15/16 April 2017: total thyroidectomy with left inferior parathyroid autotransplantation on the posterior margin of the SCM; anatomopathological report: 1.1x0.8x0.6 cm unique tumour in the left lobe, no lymph nodes involvement and no parathyroid glands May 2017: TSH=2,1 mUI/ml on Levothyroxine; undetectable calcitonin, PTH: 14.4 pg/ml (15-65), normal serum 25 OH vitamin D and Calcium (on cholecalciferol and calcium supplement); March 2019: left breast conservative surgery for DCIS (ER-, PRG-, HER 3+, Ki67-30%) with negative sentinel lymph node biopsy – followed by radiotherapy (42 Gy- June 2019) June 2020: PTH =8.3 pg/ml (15-65), CaT=9.6 mg/dl (8.8-10.4) (on cholecalciferol and calcium supplement); Nov 2020: PTH =12.4 pg/ml (nr 15-65), CaT=8.77 mg/dl (8.8-10.4), 25 OH vitamin D: 40 ng/ml (n>30) (on cholecalciferol and calcium supplement); TSH=1.32 mUI/l (on Levothyroxine); converted to alphacalcidiol (active vitamin D) Clinical exam – 59 kilo/ 169 centimetres, Trousseau negative, euthyroid, postoperative scars following surgeries.

Discussion: Permanent hypoparathyroidism is a recognized complication of thyroidectomy. Parathyroid autotransplantation (PTHAT) has been performed to avoid permanent hypoparathyroidism. The incidence of transient hypocalcemia due to hypoparathyroidism is higher in patients who underwent PTHAT but, rarely permanent hypoparathyroidism occurs. In our patient, a recovery of the transient hypoparathyroidism was documented 6 months following neck surgery – with a rebound of the hypoparathyroidism and a nadir 12 months following radiotherapy in the ipsilateral breast area- with gradual recovery.