Endocrine Abstracts

Background: Approximately 25% of patients with parathyroid carcinoma (PC) have metastases; the most frequent sites include cervical lymph nodes (30%) and lungs (40%). Less common are liver, bones and brain. Surgical resection of local or distant metastases (if possible) provides the best control of hypercalcemia and enhances long-term survival.

Case description: A 70-year old patient was admitted to hospital with a primary hyperparathyroidism (PH). He did not display disease specific signs or symptoms. Blood biochemistry resulted: severe hypercalcemia (total calcium – 3.21 (2.15–2.55)), elevated PTH level - 543 pg/mL (15–65). Ultrasound (US) examination and 99 mTc-Sestamibi (99 mTc-MIBI) scintigraphy detected a tumor of right lower parathyroid gland (PG) – 19 × 22 × 35 mm. A surgical treatment did not lead to remission of the PH, the parameters of phosphorus-calcium metabolism remained on the same levels. The histological examination demonstrated vascular, adipose tissue and capsular invasion regarded as PC. CT-scan showed no evidence of metastatic lesions in lungs, mediastinum, liver, kidneys and adrenal glands. However, PET/CT with 18F-fluorocholine revealed a pathological accumulation focus of 18F-fluorocholine (SUV 8.42) in the arch of VI thoracic vertebra (ThVI). The focus measured up to 20 × 12 × 25 mm. with a displacement of the structural-dural sac at this level. Normal bone tissue in this lesion was replaced by pathological soft tissue. 99 mTc-MIBI full-body scintigraphy showed a high MIBI uptake only in the ThVI. Thus, a decompression laminectomy of ThVI with transpedicular fixation of ThV-ThVII was successfully performed with normalization of PTH and Ca levels (48 pg/ml (15–65) and 2.48 mmol/l (2.10–2.55) respectively). The histological and immunohistochemical examination confirmed the parathyroid metastasis. Another 99 mTc-MIBI scan showed no pathological uptake in the whole body. The last follow-up in a year after the surgery confirmed the disease remission (PTH 35 pg/ml, Ca 2.3 mmol/l). The patient continues regular monitoring in our center.

Conclusion: Distant local PC metastases could be successfully surgically removed to achieve laboratory remission of the disease.