[en] There have been several similar reports of a high incidence of parathyroid tumours in rats and in man following either exposure of the head and neck to radiation or administration of iodine-131 at a young age. It is suggested that all patients with hyperparathyroidism should be questioned about radiation exposure, and that patient known to have had such therapy in childhood should be tested for asymptomatic hyperparathyroidism. (U.K.)