Hypercalcaemia; is it primary hyperparathyroidism or malignancy with bony metastasis, or both? Adnan Agha, Mahendra Yadagiri, Vahesh Katreddy, Fahmy Hanna Department of Diabetes and Endocrinology , Royal Stoke Hospital, University Hospitals North Midlands Background: Hypercalcaemia is seen commonly in malignancy associated with bony metastasis secondary to local osteolytic process, which along with humoral hypercalcaemia of malignancy is responsible for majority of patients with hypercalcaemia requiring hospitalization. Here we attempt to describe a case of hypercalcaemia with difficulty in identifying the underlying cause due to presence of concomitant pathology. Specific Results & Treatment: Enhanced CT scan showed metastasis spread to lung and liver with further bony metastasis into iliac crest, ribs and sacrum seen on the isotope bone scan as compared to previous. Thus the preliminary diagnosis of hypercalcaemia of malignancy was made. However to rule out other causes of hypercalcaemia, as the patient’s calcium levels were normal previously despite having lytic lesion in April 2013, parathyroid hormone was checked which came back high at 16.5 pmol/L. The differentials to consider were local osteolytic related hypercalcaemia of malignancy with secondary hyperparathyroidism due to vitamin D deficiency or Primary hyperparathyroidism causing hypercalcaemia on background of malignancy or a combination of both. Investigating further with MIBI scan confirmed the diagnosis of parathyroid adenoma. (See Figure 1) Date Labs Values Normal 18/10/14 Calcium 2.72 2.2-2.6 mmol/l 24/10/14 2.45 Adj Calcium 3.02 2.2- 2.6 mmol/l 2.85 Phosphate 0.8 0.8-1.5 mmol/l PTH 16.5 0 - 7.6 pmol/l Vitamin D3 None Total > 50 nmol/l Urea 8.5 2.5- 7.8 mmol/l Vitamin D2 35.7 Creatinine 108 55- 108 umol/l Case History: A 74 year old male with background of prostate carcinoma with bony metastasis on androgen deprivation therapy for last 18 months, on long term catheter and Meniere’s disease, came into Acute Medical Unit with new onset confusion for the last three days. On physical examination no neurological findings or focus of infection was identified. Table 1: Laboratory data of the patient (patient received IV bisphosphonates on 19/10/2014) Investigation: Urine dipstick was positive to leucocytes and nitrites, but no raised markers of inflammation were found, still antibiotics were tried with no improvement. The blood work was all within normal limits except adjusted calcium of 3.02 mmol/L and low Vitamin D. (See Table 1) Figure 1: MIBI scan showing increased uptake suggestive of parathyroid adenoma in the posterior part of right thyroid gland The patient improved with intravenous bisphosphonate. The patient was referred for possible parathyroidectomy, however he developed hospital acquired pneumonia and the plans were deferred. Conclusions: Parathyroid adenoma on background of unrelated prostate malignancy with hypercalcaemia. Points for discussion: The case highlights the importance of checking of parathyroid hormone, vitamin D and calcium levels together in patients with hypercalcaemia to confirm the diagnosis. It is important to remember that hypercalcaemia in malignancy is not always malignancy associated hypercalcaemia.