SUN-501 Parathyroid Autoinfarction Presents as a Neck Mass and Resolution of Hypercalcemia

Background: Parathyroid autoinfarction or “parathyroid apoplexy” is a phenomenon in which parathyroid gland become spontaneously hemorrhagic or infarcted. Parathyroid autoinfarction is rare. Few cases were reported previously. Here we describe a case of Parathyroid autoinfarction. Clinical case: A 42-year old female patient with history of Graves’ disease on Methimazole found to have high calcium on routine blood work. Her calcium was 11.1 mg/dl. (Normal range: 8.2- 10.6 mg/dl), albumin 4.3 gm/dl. (Normal range: 3.5-5.7 gm/dl). Reviewing her charts revealed hypercalcemia for several years. Ranges between (10.1 and 11.2 mg/dl) with an average of 10.7mg/dl. Primary hyperparathyroidism was suspected. She was supposed to have full evaluation of hypercalcemia including PTH measurement, Vit D and urinary calcium on her coming follow up appointment. However, prior to her follow up, she presented to Emergency room with three-day history of right sided neck pain, hoarseness and difficulty swallowing. On exam, she had very tender neck on the right side with palpable swelling. CT scan of the neck with contrast showed 3.1 cm x 1.2 cm x 1.7 cm hypo enhances solid mass posterior to the right thyroid lobe and within the region of the tracheoesophageal groove which could contribute to recurrent laryngeal nerve dysfunction. Labs showed a drop of calcium level to 8.9 mg/dl, albumin:3.5 mg/dl, and PTH :31 Pg /ml (normal range :12-88 Pg /ml). US guided FNA biopsy of the mass showed scant connective tissue and parathyroid tissue. Due to the concern of laryngeal nerve compromise, she underwent surgical removal of the mass. Surgical pathology showed enlarged parathyroid gland with hemorrhagic infarction. Based on clinical presentation and histopathology, diagnosis of parathyroid autoinfarction was made. Conclusion: Rapid reduction of calcium in patient with primary hyperparathyroidism should raise suspicion of parathyroid autoinfarction, especially if local neck symptoms are present. Though spontaneous resolution of primary hyperparathyroidism following parathyroid autoinfarction is possible, recurrence can occur. Parathyroidectomy is more common approach than conservative management. Surgery should be considered if recurrent laryngeal nerve is compromised by mass effect of infarcted gland.