Paradoxical cerebral embolism caused by patent foramen ovale in a patient with multiple endocrine neoplasia type 1 and severe primary hyperparathyroidism

A man in his late 30s with gait difficulty, dysarthria, impaired consciousness and polyuria was diagnosed with left thalamic infarction. Hypercalcaemia (3.52 mmol/L (2.15–2.52)), high intact-parathyroid hormone (i-PTH) levels (88.8 pmol/L (1.1–6.9)) and high D-dimer levels (14.7 mg/L (<1.0)) were identified, followed by a positive microbubble test on transesophageal echocardiogram, suggesting high-risk patent foramen ovale (PFO) for ischaemic stroke. Paradoxical cerebral embolism via PFO, complicated by a hypercoagulable state and hypercalcemic dehydration, was considered. Polyglandular parathyroid hyperplasia, plus radiolucent mandibular tumours, suggested multiple endocrine neoplasia type 1 (MEN1) or hyperparathyroidism-jaw tumour syndrome. Genetic testing confirmed MEN1. Treatment was 24 mg of oral evocalcet and total parathyroidectomy with forearm autotransplantation, resulting in improved serum calcium and i-PTH levels. Finally, he underwent transcatheter PFO closure. We emphasise careful, etiological pursuit in young-onset stroke and the usefulness of genetic testing in differentiating hyperparathyroidism associated with mandibular tumours.