Objective: The objective of this report was to describe an unusual case of emerging primary hyperparathyroidism (PHPT) accompanied by recovery of parathyroid blood flow 3 months after spontaneous parathyroid hemorrhage.
Methods: Neck images and laboratory tests including serum calcium and parathyroid hormone (PTH) were performed to evaluate parathyroid hemorrhage. Pathologic findings after parathyroidectomy are also presented.
Results: A 58-year-old woman developed acute onset of neck pain and swelling with ecchymosis. Computed tomography showed a right paratracheal hematoma-like lesion behind the thyroid. Ultrasound (US) of the neck revealed a round, hypoechoic nodule measuring 27 × 25 × 18 mm in the right lower thyroid pole without vascular flow. Blood tests showed a corrected calcium of 9.3 mg/dL (normal, 8.7 to 10.3 mg/dL), and intact PTH of 68 pg/mL (normal, 10 to 65 pg/mL). Intact PTH measurement in fine-needle aspirate of the lesion was 339 pg/mL, confirming parathyroid origin. Repeat US after 3 months showed a remarkable decrease in lesion size with significant blood flow. Blood biochemistry showed a corrected calcium of 10.9 mg/dL, and an intact PTH of 237 pg/mL. She eventually underwent parathyroidectomy, and pathologic examination revealed parathyroid adenoma with a tiny thrombus.
Conclusion: Spontaneous remission of PHPT after parathyroid hemorrhage has been known to occur sporadically, a phenomenon referred to as autoparathyroidectomy. Although spontaneous remission with permanent improvement of PHPT may be observed, PHPT can recur in the relative short term after parathyroid hemorrhage, and so follow-up blood biochemistry surveillance is necessary. Also, evaluating parathyroid blood flow using color Doppler US might be useful in verifying the recurrence of PHPT.