RESUMO
Most mediastinal parathyroid tumours lie within the thymus gland and may be retrieved when cervical thymectomy is carried out in the course of neck exploration for primary hyperparathyroidism (HPT). We report 4 patients, each of whom required sternotomy for removal of a true mediastinal parathyroid adenoma. Subtraction isotope scintigraphy suggested the presence of a mediastinal tumour prior to cervical exploration in 2 individuals and prior to re-exploration in a third. When localisation before initial exploration for HPT suggests a parathyroid tumour within the chest, consideration should be given to proceeding to sternotomy, at first operation if a comprehensive neck exploration, including cervical thymectomy, fails to uncover the adenoma. Uniquely, one of our patients underwent sternotomy for HPT when 23 weeks pregnant.