SUN-491 An Uncommon Presentation of Primary Hiperparathyroidism

We present a case of primary hyperparathyroidism with an uncommon presentation. The patient is a 71-year-old man with a personal history of hypertension, dyslipidemia, chronic obstructive pulmonary disease. He appealed to the emergency service several times with complaints of chronic constipation, abdominal pain, nausea, vomiting, fainting, anorexia, asthenia, intermittent fever, with about 3 months of evolution. He also had weight loss of 15-20 kg in the last 6 months.He was admitted at our hospital to study the wasting syndrome.Several tests were performed, standing out hypercalcemia (serum calcium corrected for albumin of 14 mg/dL), parathormone (PTH) 721 pg/ml, with acute renal injury. Computed tomography (CT) covering the cervical region revealed a 4,7 cm cystic nodule with apparent starting point at the lower pole of the right thyroid lobe. Cervical ultrasound showed a massive cystic lesion with 48 mm adjacent to the lower right posterior border of the right thyroid lobe, consistent with CT scan. Parathyroid scintigraphy did not show scintigraphic evidence of parathyroid tissue, namely in ectopic localization.Ultrasond-guided cytology was performed, with aspiration of cystic content and PTH assay in wash was >2500 pg/mL. During hospitalization, the patient was treated with bisphosphonate and intensive fluid therapy, with normalization of serum calcium and resolution of symptoms. He had hospital discharge with cinacalcet, referred for surgery. About 4 weeks later, he got again with severe hypercalcemia and symptoms. He was admitted again for calcium normalization. After therapy, he had hospital discharge with improvement of symptoms and maintained cinacalcet in higher dose. At this moment, he is waiting for surgery. The blood tests revealed primary hyperparathyroidism with symptomatic hypercalcemia. Although scintigraphy does not show radiopharmaceutical uptake, CT scan and ultrasound showed a probable adenoma of the lower right parathyroid. In these cases, the exploratory surgical approach will be recommended. The most common presentation of primary hyperparathyroidism is mild to moderate asymptomatic hypercalcemia. However, the presentation may be atypical, confusing the diagnosis. In this case, early diagnosis was essential for treatment, avoiding even more serious complications such as a parathyroid crisis.