Endocrine Abstracts

Parathyroid carcinoma, a rare endocrine malignancy, accounting for only 1–2% of patients with primary hyperparathyroidism (HPT). In addition, a few case have been reported coexistence of parathyroid carcinoma and papillary thyroid cancer. Here, we present a case of recurred parathyroid cancer with multiple lymph node metastasis. A 57-year-old women was presented with high serum calcium level (14.4 mg/dl) in medical check-up. Hyperparathyroidism was considered to be the reason of hypercalcemia because of significantly increased parathyroid hormone (PTH, 1275 pg/ml) levels. Neck ultrasonography (US) at that time showed 0.7~4.5 cm sized multiple thyroid nodules at both lobes. Tc-99m sestamibi scan demonstrated marked increased radiotracer activity in the region of the inferior left lobe of the thyroid. She underwent left parathyroidectomy, total thyroidectomy and central compartment lymph node dissection. Histopathology revealed that the 4.5 cm mass adjacent to the left thyroid lobe was a parathyroid carcinoma with evidence of vascular invasion. As well, she was found to have a 1.3 cm papillary thyroid cancer in the right thyroid lobe and a 1.5 cm follicular adenoma in the left side. Serum calcium and PTH returned to the normal range after surgery, but she developed a recurrence 2 years later (2 × 0.5 cm, isoechoic nodule at left operative bed). Re-exploration revealed recurrence at the previous surgery site. Positron emission tomography-computed tomography (PET-CT) revealed intense hypermetabolic lesions on Left operative bed and cervical level VI, VII, and whole body bone, which were thus thought to be local recurrence of parathyroid cancer. At third operation, 5×9 cm sized soft, well demarcated mass was found at previous op site, and enlarged lymph nodes were detected at level coincide with PET-CT image. Pathologic report confirmed diagnosis of metastatic parathyroid carcinoma.