The Elusive And Protracted Primary Hyperparathyroidism With Mandibular Tumours

Primary hyperparathyroidism is a disease that predominantly affects women in the postmenopausal age while osteitis fibrosa cystica or browns tumor, is now a rare manifestation of the disease. Hyperparathyroidism-jaw tumor syndrome on the other hand, is a rare hereditary form of primary hyperparathyroidism which is associated with jaw tumors, renal abnormalities and parathyroid carcinoma. We report a 41-year-old Indian lady who was diagnosed with primary hyperparathyroidism with brown tumor at the age of eleven. She presented with multiple jaw tumours and pseudoclubbing which were associated with high calcium, low phosphate and an elevated parathyroid hormone level. The ALP levels were raised with normal renal and liver profiles. Her X-rays showed multiple bone cysts in the mandible with bony resorption at the terminal phalanges while the ultrasound of the kidneys was normal. She underwent neck exploration twice in the 1990s, unfortunately on both occasions the surgery failed to localise the parathyroid adenoma. Subsequently multiple radiological investigations were employed to locate the elusive parathyroid adenoma including repeated ultrasounds, CT scan of the neck and mediastinum, thallium scan and even cervical venous sampling. However, all failed dismally. She subsequently refused a third explorative neck surgery and was followed up in our clinic throughout these years with intermittent oral phosphate supplement while her calcium levels remained persistently below 3 mmol/l. Surprisingly she did not develop any new lesions in the jaw during this long period of observation. Of late she started to develop medullary nephrocalcinosis with hypertension, while the BMD remained normal. As a result of this new development she had consented for a third surgery. A subsequent sestamibi scan showed uptake in what may possibly be the tracheal oesophageal groove. A FDG PET scan is planned to corroborate the findings of the sestamibi scan and will be presented during the meeting. She is scheduled for a repeat exploratory surgery in our institution. This case highlights several issues, namely the patient is likely to have an ectopic parathyroid adenoma. Naturally a third neck exploration is associated with higher morbidity and failure rate, thus it is important to localize the adenoma preoperatively using the appropriate imaging modalities aided by an intra-operative ultrasound. Another consideration is whether the patient has hyperparathyroidism-jaw tumor syndrome due to the predominant involvement of the jaw. However in the absence of family history, the mild degree of hypercalcaemia and the long protracted history made it highly unlikely. Department of Medicine, Universiti Kebangsaan Malaysia Medical Centre (UKMMC) Jalan Yaacob Latiff, Bandar Tun Razak, Cheras 56000, Kuala Lumpur