The patient in the question is not a good candidate for surgical removal of parathyroid mass due to the underlying medical complications, so ultrasound guided alcohol injection is the most appropriate treatment. Ultrasound guided alcohol injection of the mass is used as an alternate therapy for patients with primary hyperparathyroidism who refuse surgical treatment, who are not good surgical candidate or who present as an emergent life threatening malignant hypercalcemia. It is most commonly used postoperatively in patients with recurrent or persistent hyperparathyroidism who have a sonographically visible residual mass. Ref: Core Topics in Endocrinology in Anaesthesia and Critical Care By George Hall, Page 36; Ultrasound: A Practical Approach to Clinical Problems By Edward I. Bluth, Page 626