D2 MTE3 Case 7: Localising parathyroid gland

A 56 year old lady walked into our clinic with history of bilateral renal calculi and generalised weakness of 6 months duration. She was known to have well- controlled hypertension on medications. Clinical examination did not reveal any positive findings. She had been seen by a visiting Endocrinologist in Maldives twice, administered calcium and vitamin D. She also underwent tests to rule out osteoporosis, (17/09/2019) PTH- 180 pg/mL [10.0-65.0] and Serum Calcium levels: Total-11.3 mg/dl [8.0-10.5], Ionised-6.12 mg/dl [4.40-5.30], Vitamin D: 38.6 ng/ml [30-80], renal function was normal. She underwent CT Contrast for Neck & Thorax for Parathyroid adenoma on 28/09/2019 which showed suspicious nodular enhancing lesion in the left lobe of the thyroid (7x4 mm in the trachea-oesophageal groove). In view of her raised PTH, Sestamibi scan done revealed no definite evidence but Methyl-Choline scan showed hypodense area in the left lobe of the thyroid. She therefore underwent surgical exploration of left minimally invasive Parathyroidectomy on 28/09/2019. Frozen section showed Parathyroid hyperplasia hence underwent 3 and a half parathyroid excision on 30/09/2019. HPE report did not reveal any parathyroid adenoma. Post-operatively, Serum PTH and Calcium levels remained high (229.5 and 11.5 mg/dl, Ionised-5.97 mg/dl). Patient later underwent excision of lymph node and left lobe of thyroid on 02/01/20 in view of persistent hyperparathyroidism. However, on biopsy it showed reactive nodes and thyroid tissue with colloid filled follicles. We still faced persistent elevation of Serum PTH and Calcium. Hence it was decided to start the patient on Cincalcet 30 mg daily after a joint meeting with surgical and nephrology consultants. Patient was not able to follow up due to the covid pandemic. Presently, her PTH -288.2, Serum Calcium-11, Vitamin D- 33.2, Phosphorus-2.9 (October 2021). This clearly shows the treatment has not been effective and we are dealing with persistent hypercalcaemia, hyperparathyroidism and no localisation. We are also faced with the problem of post-operative management of hypercalcaemia. How to manage persistent hypercalcaemia and hyperparathyroidism? How to proceed with localisation of the primary source of PTH?