Endocrine Abstracts

Context: Cystic adenomas of the parathyroid gland are relatively rare, with an estimated incidence of 0.3-1.5% of all parathyroid tumors. These tumors are benign and typically present as a single cyst or multiple small cysts within a solid nodule. Due to their rarity and nonspecific imaging features it may be challenging to diagnose preoperatively. However, the diagnosis is confirmed by fine-needle aspiration (FNA) biopsy and pathological examination of the tissue obtained by FNA.

Case Illiustration: We report the case of a 69-year-old woman admitted to endocrinologist’s due to increased sweating and worsening eyesight. The patient had a multifocal goitre that did not require any particular treatment. She was found to have hypercalcemia (2.95 mmol/l; normal: 2.2-2.65 mmol/l), hypercalciuria (10.03 mmol/24 h; normal 0-6.2 mmol/24 h) and elevated PTH (26.4 pmol/l; normal: 1.26-6.74 pmol/l). The plasma phosphorus (0.86 mmol/l; normal: 0.81-1.45 mmol/l), urine phosphorus (30.0 mmol/24 h; normal: 12.9-42 mmol/24 h) and 25-hydroxyvitamin D (76.60 nmol/l; normal: 70-250 nmol/l) were normal. There was no renal failure or osteoporosis. Ultrasonography of the neck revealed a 1.4×0.7×0.9 cm cystic mass below the left lobe of the thyroid gland. The nodule found in ectopic thyroid tissue had a mixture of solid and cystic components, this is not a typical feature of a parathyroid gland. SPEC/CT of the neck and mediastinum with 99mTc-MIBI was performed. There was no evidence of accumulation of radiopharmaceutical 99mTc-MIBI, the absence of a parathyroid adenoma was confirmed. As a result of the high previous suspicion of the parathyroid adenoma, it was decided to conduct a fine-needle aspiration of the solid nodule. Cytological and biochemical tests (PTH analysis in rinse material revealed high PTH (210.6 pmol/l)) confirmed parathyroid gland. The multidisciplinary consortium made the decision that surgical treatment is the most appropriate treatment for a parathyroid adenoma. After a parathyroidectomy, histological examination was performed, the diagnosis of a cystic parathyroid adenoma was confirmed. Additionally, post-operative laboratory tests showed normal levels of calcium (2.44 mmol/l) and PTH (2.03 pmol/l) which indicates that surgery was successful.

Discussion: Cystic parathyroid adenomas are rare and have unique characteristics that can make them challenging to diagnose and treat. An experienced endocrine surgeon and multidisciplinary team approach is recommended to manage these cases.