Double water-clear cell parathyroid adenoma: a case report and literature review

Water-clear cell parathyroid adenoma is an uncommon cause of primary hyperparathyroidism. Herein, we report an interesting case of a 56-year-old man who presented with weight loss, bone pain, fatigue, and a palpable right neck mass. Laboratory tests indicated hypercalcemia, elevated parathyroid hormone (PTH) levels, and normal thyroid function. Further examinations detected osteoporosis and kidney stones. The ultrasound of neck revealed bilateral extrathyroidal tumors, which were sestamibi-avid. The patient underwent resection of the large right inferior and left inferior parathyroid tumors. Histopathology revealed a double water-clear cell parathyroid adenoma. His serum calcium and PTH levels normalized after surgery. The literature review identified 37 cases of water-clear cell parathyroid adenoma between 1985 and 2021. The median age at diagnosis was 56 years. Classic complications were common, including nephrolithiasis in nine and skeletal presentations in 10 patients. Before surgery, the median calcium and PTH levels were 12.0 mg/dL and 290 pg/mL, respectively. Overall, 89% were localized on ultrasonography, and 60% were positive on scintigraphy. Four patients had double adenomas. The median maximum diameter was 3.8 cm, and the median weight of the resected adenoma was 5.27 g. In summary, water-clear cell parathyroid adenoma has certain unique features. These include larger tumor size, relatively indolent biochemical profile, high prevalence of complications and nonspecific symptoms, an isoechoic appearance on ultrasonography, and reduced scintigraphic sensitivity.