Cured primary hyperparathyroidism after fine-needle aspiration biopsy-induced parathyroid disappearance

Summary Spontaneous or fine-needle aspiration (FNAB)-induced remission of primary hyperparathyroidism (PHPT) may occur, especially for cystic lesions. However, the disease generally relapses over a short time period. We present a case of PHPT due to an enlarged hyperfunctioning parathyroid that underwent long-term (almost 9 years) clinical and ultrasonographic remission after the disappearance of the lesion following ultrasound (US)-assisted FNAB. A 67-year-old woman with PHPT underwent biochemical and US examinations that confirmed the diagnosis and showed a lesion suggestive for parathyroid adenoma or hyperplasia. US-FNAB of the lesion confirmed its parathyroid nature by means of elevated levels of parathyroid hormone within the needle washing fluid. At the second visit, the patient referred slight neck swelling that resolved spontaneously in the days after the US-FNAB. At subsequent follow-up, the enlarged parathyroid was not found; it was visible neither with US nor with magnetic resonance imaging. Biochemical remission persists after 9 years. This is the first reported case of cure of PHPT after US-FNAB performed on a hyperfunctioning parathyroid resulting in its complete disappearance over a period of 9 years of negative biochemical and ultrasonographic follow-up. Learning points: Spontaneous or fine-needle aspiration-induced remission of primary hyperparathyroidism can occur. Both circumstances may present disease relapse over a variable time period, but definite remission is also possible even though long-term periodic follow-up should be performed. Parathyroid damage should be ruled out in case of neck symptomatology after parathyroid fine-needle aspiration or spontaneous symptomatology in patients with history of primary hyperparathyroidism.