Two cases of spontaneous remission of primary hyperparathyroidism due to auto-infarction: different management and their outcomes

Spontaneous remission of primary hyperparathyroidism (PHPT) due to necrosis and haemorrhage of parathyroid adenoma, the so-called ‘parathyroid auto-infarction’ is a very rare, but previously described phenomenon. Patients usually undergo parathyroidectomy or remain under close clinical and biochemical surveillance. We report two cases of parathyroid auto-infarction diagnosed in the same tertiary centre; one managed surgically and the other conservatively up to the present time. Case #1 was a 51-year old man with PHPT (adjusted (adj.) calcium: 3.11 mmol/L (reference range (RR): 2.20–2.60 mmol/L), parathyroid hormone (PTH) 26.9 pmol/L (RR: 1.6–6.9 pmol/L) and urine calcium excretion consistent with PHPT) referred for parathyroidectomy. Repeat biochemistry 4 weeks later at the surgical clinic showed normal adj. calcium (2.43 mmol/L) and reduced PTH. Serial ultrasound imaging demonstrated reduction in size of the parathyroid lesion from 33 to 17 mm. Twenty months later, following recurrence of hypercalcaemia, he underwent neck exploration and resection of an enlarged right inferior parathyroid gland. Histology revealed increased fibrosis and haemosiderin deposits in the parathyroid lesion in keeping with auto-infarction. Case #2 was a 54-year-old lady admitted with severe hypercalcaemia (adj. calcium: 4.58 mmol/L, PTH 51.6 pmol/L (RR: 1.6–6.9 pmol/L)) and severe vitamin D deficiency. She was treated with intravenous fluids and pamidronate and 8 days later developed symptomatic hypocalcaemia (1.88 mmol/L) with dramatic decrease of PTH (17.6 pmol/L). MRI of the neck showed a 44 mm large cystic parathyroid lesion. To date, (18 months later), she has remained normocalcaemic. Learning points: Primary hyperparathyroidism (PHPT) is characterised by excess parathyroid hormone (PTH) secretion arising mostly from one or more autonomously functioning parathyroid adenomas (up to 85%), diffuse parathyroid hyperplasia (<15%) and in 1–2% of cases from parathyroid carcinoma. PHPT and hypercalcaemia of malignancy, account for the majority of clinical presentations of hypercalcaemia. Spontaneous remission of PHPT due to necrosis, haemorrhage and infarction of parathyroid adenoma, the so-called ‘parathyroid auto-infarction’, ‘auto-parathyroidectomy’ or ‘parathyroid apoplexy’ is a very rare in clinical practice but has been previously reported in the literature. In most cases, patients with parathyroid auto-infarction undergo parathyroidectomy. Those who are managed conservatively need to remain under close clinical and biochemical surveillance long-term as in most cases PHPT recurs, sometimes several years after auto-infarction. Background Primary hyperparathyroidism (PHPT) is characterised by excess parathyroid hormone (PTH) secretion arising mostly from one or more autonomously functioning parathyroid adenomas (up to 85%), parathyroid hyperplasia (<15%), and in 1–2% of cases from parathyroid carcinoma (1). PHPT with its prevalence of approximately 1:1000 (2, 3) is a relatively common condition and, together with hypercalcaemia of malignancy accounts for the majority of clinical presentations of hypercalcaemia. Parathyroidectomy has been considered the only definitive cure, however, watchful waiting with monitoring for the presence of end-organ damage is also warranted in selected cases (4). Over last decades, several cases of spontaneous remission of PHPT have been reported and attributed to spontaneous necrosis, haemorrhage and infarction of parathyroid adenoma and this phenomenon has been referred to as ‘parathyroid auto-infarction’, ‘auto-parathyroidectomy’ or ‘parathyroid apoplexy’ (5, 6, 7, 8, 9). In this report we present two cases of spontaneous resolution of PHPT due to parathyroid auto-infarction, one of which was managed surgically and the other one conservatively. We discuss their outcomes, prognosis and the strategy for long-term management of patients with this presentation.