Introduction: Postmortem studies have shown that a fifth parathyroid gland may be present in about 5% of patients with hyperparathyroidism. 1% of parathyroid glands are located in thyroid tissue. Theres a prevalence of 710% of thyroid ectopic tissue.
Case report: A 53-year-old male, submitted to bilateral nephrectomy due to a Grawitz tumour at the age of 25. Under haemodialysis since then (with a rejected renal transplant in the past), he was recently referred to our department with a tertiary hyperparathyroidism diagnosis. Treated intra-hemodialysis with alfacalcidol 0.25 μg and cinacalcet. Analytically had a PTH 1604 pg/ml, calcium 9.5 mg/dl, phosphorus 5.6 mg/dl, and creatinine 11.4 mg/dl. Cervical ultrasound did not identify parathyroid gland and thyroid scintigraphy suggested parathyroid adenoma in the bottom right. PET-scan showed bone lesions suggestive of brown tumours. The patient was submitted to surgery and has removed four parathyroid glands (920 mm) with an histology of nodular hyperplasia of the parathyroid. Was also removed a fifth nodule located in the lower left region with 9 mm, described as focus of parathyroid in parenchyma thyroid (intra-thyroid parathyroid?). Three months after surgery hes treated with 1 g of calcium carbonate (3+3+3) and 0.25 μg calcitriol (1+0+1), with PTH 139 pg/ml, calcium 8.2 mg/dl, and phosphorus 2.6 mg/dl.
Conclusions: In this patient despite scintigraphy suspicion of a functioning parathyroid adenoma, since it is a tertiary hyperparathyroidism, we chose surgical exploration with resection of all parathyroid glands. It was found a fifth focus of parathyroid tissue within an ectopic thyroid tissue. This case presents the association of three relatively rare situations: supernumerary parathyroid gland, in thyroid tissue in an ectopic location.