Endocrine Abstracts

Introduction: Hypercalcemia is not uncommon in clinical practice and may present as a life-threatening emergency. Its main aetiologies are primary hyperparathyroidism (80% parathyroid adenomas; 20% multiglandular hyperplasia, <1% parathyroid carcinomas) and hypercalcemia of malignancy, with or without presence of bone metastases.

Case Report: We present a case of a 77 years-old male, submitted to a subtotal gastrectomy at the age of 73 due to a perforated duodenal ulcer and a partial right nephrectomy due to clear cell renal carcinoma limited to the kidney at the age of 74, under annual surveillance. Admitted for severe hypercalcemia associated with acute chronic low back pain in the last two months, gait imbalance, loss of strength in the lower limbs, anorexia, weight loss of 3 kg, polyuria and polydipsia. He was dehydrated, with temporal-spatial disorientation and confusion. Cranial-CT was normal, and EMG showed an axonal sensory-motor peripheral polyneuropathy with sensory predominance. His blood tests revealed PTH 1392 pg/ml, ionized calcium 2.29 mmol/l, total calcium 4.06 mmol/l phosphorus 0.81 mmol/l, vitamin D 20 nmol/l, alkaline phosphatase 193 U/l, Creatinine 1.78 mg/dl. Cervical ultrasound suggested a parathyroid adenoma and TC-99 Sestamibi scintigraphy corroborated parathyroid adenoma/hyperfunctioning left upper parathyroid tissue. Abdominal / pelvic CT excluded renal lithiasis and local recurrence of the renal neoplasm, however exposed focal lytic lacunar lesions in the lumbar vertebral, the largest in L3, suggestive of lytic metastasis and signs of bone demineralization. Bone biopsy of the vertebral lesion showed marked hypocellularity, edema and fibrosis, without osteoclasts or malignant cells. Protein electrophoresis and urinary immunofixation was not suggestive of monoclonal gammopathy. He underwent surgical excision of the parathyroid with 2.6×1.5×1 cm and pre-op PTH 661.0 pg/ml and at 15 min 130.0 pg/ml whose anatomopathology confirms a non-capsulated parathyroid gland or only partially covered by a thin capsule, consisting of proliferation of principal cells without cytological atypia, rare figures of mitosis and necrosis, and with no images of vascular or perineural invasion.

Discussion: Despite considering the hypotheses of tumour hypercalcemia due to PTHrP or secondary to osteolytic metastases, PTH values do not favour them. The case raises the possibility of an Atypical Parathyroid Adenoma. Only long-term follow-up with surveillance of local recurrence and distant metastases will allow a correct diagnosis.