Endocrine Abstracts

We would like to present a case of primary hyperparathyroidism presumably present with clinically large cystic parathyroid adenoma with multiple destructive skeletal lesions, which is of course referred to bone metastases.

Case: A 58-year-old male patient was admitted to the orthopedy polyclinic with left leg pain and on the MR imaging performed here, multiple lytic lesions compatible with metastasis to the tibia and fibula were detected. He was directed to our internal medicine clinic for further investigation. The patient had complaints of widespread bone pain, especially the left leg which lasted for 2 months and was suffering from polydipsia. Biochemical tests showed elevated serum calcium values and increased intact parathyroid hormone (iPTH), low phosphorus, high alkaline phosphatise, compatible with primary hyperparathyroidism. Erosive and brown tumour like lesions were detected in bone x-ray. On PET CT imaging, extensive, lytic and expansile lesions were observed, especially in the kranium and ribs. On the neck ultrasonography, a 50×30 mm sized, septated, irregular contour nodule was detected in the right lobe. Thyroid fine needle aspiration biopsy was performed. Histopathological evaluation was benign and there were no findings indicating parathyroid pathology. Parathyroid scintigraphy showed no lesions compatible with neck or mediastinal adenoma. Due to resistant hypercalcemia, the patient was given bilateral neck exploration. The parathyroid mass was localized and resected intraoperatively in the lower pole of the thyroid nodule extending mediastinum, and histopathological evaluation was compatible with parathyroid adenoma. Biochemical results due to hyperparathyroidism normalized after operation and complaints resolved.

Discussion: It should be considered that primary hyperparathyroidism may have bone lesions that mimic bone metastasis. Especially in cases where the thyroid nodule is visible but there is no evidence of parathyroid adenoma in parathyroid scintigraphy intrathroidal parathyroid adenomas should be considered in the differential diagnosis of cystic neck lesions.