Ectopic And Supernumerary Parathyroid Glands In Patients With Secondary And Tertiary Hyperparathyroidism
*Robert J Reitz, III1, Christopher T. McHenry2, *Edward Horwitz2, *Alina Khil3
1Case Western Reserve School of Medicine/MetroHealth Medical Center, Cleveland, OH;2MetroHealth Medical Center, Cleveland, OH;3Case Western Reserve School of Medicine, Cleveland, OH
Ectopic and supernumerary parathyroid glands are causes for failed parathyroidectomy. The aim of this study was to determine the rate of ectopic and supernumerary parathyroid glands in patients with secondary (20) and tertiary (30) hyperparathyroidism (HPT). We hypothesized that hyperplasia of ectopic and supernumerary parathyroid glands are a potential significant cause for persistent disease in patients undergoing parathyroidectomy for 20 and 30 HPT.
Materials and Methods
A retrospective review of a prospectively maintained parathyroid database was completed to identify all patients who underwent parathyroidectomy for 20 or 30 HPT. Operative and pathology reports were reviewed, and the number and location of the parathyroid glands were determined.
From 1993-2018, 70 patients underwent subtotal parathyroidectomy or total parathyroidectomy with parathyroid auto-transplantation for 20 (n=31) or 30 (n=39) HPT; the mean age was 48 +/- 14 years and there were 38 (54%) women. Fifty-six (80%) of 70 patients were on dialysis for an average of 7.3 years. The mean intact PTH level for the entire cohort was 1857.9 +/- 1188.9 pg/ml and the mean calcium levels were 9.3 +/-0.7 mg/dl and 11.3 +/- 0.8 mg/dl in patients with 20 and 30 HPT, respectively. Of the 31 patients with 20 HPT, 4 (13%) had supernumerary parathyroid glands and 8 (25%) had ectopic parathyroid glands; 6 in the thymus, 1 in the anterior mediastinum and 1 in the prevertebral space extending into the posterior mediastinum. Of the 39 patients with 30 HPT, 6 (15%) had supernumerary glands, and 8 (20%) had ectopic glands. Five of 9 ectopic glands were intrathymic (2 were in the thymus of a single patient), and 1 each was retropharyngeal, in the tracheoesophageal groove, in the posterior mediastinum and undescended just inferior to the submandibular triangle.
Surgeons treating 20 and 30 HPT should be aware that 14% of patients have more than four hyperplastic parathyroid glands and 23% have ectopic glands. The thymus is the most common location for ectopic and supernumerary glands, underscoring the importance of transcervical thymectomy in the treatment of 20 and 30 HPT.
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