Clinical Case: Diagnostic Challenges of Intrathyroidal Parathyroid Adenoma

Introduction Intrathyroidal parathyroid adenoma is a rare anomaly with an incidence of 1.4-6% [1]. Case Presentation A 67 – years old female patient presented with 3 years of general and muscle weakness, fatigue. Anamnesis: partial gastrectomy due to stomach carcinoma, hysterectomy, osteoporosis. In the laboratory tests were found increased levels of PTH, calcium, anti-TPO and low level of vitamin D. Patient was treated with Colecalciferolum 25000 TV. In dynamics PTH increased from 26,47 to 210 pmol/l, calcium from 2,71 to 2,79 mmol/l over 4 months. Thyroid ultrasound showed EU-TIRADS 3-4. During physical examination thyroid gland was mobile, a mobile induration was palpable, no peripheral lymph nodes were detected. After 18 months thyroid ultrasound was repeated and FNA was performed. In biopsy: epithelium hyperplasia (III category of Bethesda). Thyroid scintigraphy performed: radiopharmaceutical-accumulating nodule in the right lobe of the thyroid (possibly adenoma). Radiopharmaceuticalaccumulating parathyroid glands were not visible. Radiologist suggested FNA with staining due to parathyroid gland adenoma, based on repeated thyroid scintigraphy and FNA after 4 months. It showed parathyroid gland tissue in the thyroid. Multidisciplinary team performed right hemithyroidectomy - removing right thyroid lobe with intrathyroidal hyperplastic parathyroid gland. After the biopsy report, the final diagnosis: right parathyroid gland adenoma. Status post right hemithyroidectomy. Autoimmune thyroiditis (euthyrosis). Osteoporosis. Discussion Primary hyperparathyroidism (PHPT) is a common endocrine disease. Intrathyroidal parathyroid adenoma (ITPA) is a rare reason for PHPT and site of ectopia [2]. The latter may be located ectopically in 11-25% of cases [1]. Clinical scenarios in which an ectopic parathyroid adenoma should be considered in clinical practice include patients with PHPT in whom preoperative imaging suggests the presence of an ectopic parathyroid adenoma or initial preoperative imaging fails to identify a target adenoma [3]. Conclusions Intrathyroidal parathyroid adenoma is rare disease in patient with PHPT. Diagnosis and management are challenging, and it requires a combination of tests.