Intrathyroidal parathyroid hyperplasia in tertiary hyperparathyroidism
A 41-year-old female with a 13-year history of hemodialysis for chronic renal failure underwent a kidney transplant in May 2011 without complications or rejection reactions. Blood tests performed prior to the kidney transplantation indicated that serum total calcium (Ca) and intact parathyroid hormone (iPTH) level were 9.9 mg/dl (normal, 8.2–10.4 mg/dl) and 453.3 pg/ml (normal, 14–72 pg/ml), respectively. Postoperative laboratory tests performed three months later revealed elevated serum Ca (10.4 mg/dl), which lasted for 15 months. Her iPTH level did not return to normal after kidney transplantation (Fig. ). The patient was diagnosed with tertiary hyperparathyroidism and was recommended for surgery.\nIn the preoperative evaluation, two-hour-delayed 99mTc-sestamibi scintigraphy showed increased uptake in both inferior parathyroid glands (Fig. ). Computed tomography (CT) of the neck showed a calcified nodule posterior to the right superior thyroid gland, a solid nodule in the right lower thyroid gland and an enlarged parathyroid gland posterior to the left inferior thyroid (Fig. ). Sonography (SONO) showed a benign-looking nodule in the right lower thyroid and two adjoining enlarged parathyroid glands posterior to the left lower thyroid (Fig. ). The right mid-thyroid nodule appeared benign, and a fine-needle aspiration biopsy was not performed. The right inferior parathyroid gland could not be identified in the CT or SONO findings. During neck exploration, four oval masses similar to parathyroid glands were observed (right superior: 1.7 × 1.0 cm, right inferior: 0.5 × 0.3 cm, left superior: 1.0 × 0.7 cm, left inferior: 0.8 × 0.6 cm). The left inferior parathyroid gland was partially preserved, while the other lesions were completely removed. Intraoperative frozen biopsy of the four masses revealed two cases of parathyroid hyperplasia, a parathyroid hyperplasia with a calcified nodule in the right superior area and a lymph node in the right inferior area. The right inferior parathyroid was not found during right neck exploration.\nIntraoperative iPTH levels 20 min after the parathyroidectomy were still elevated (102.6 pg/ml). A small and soft nodule (12 mm diameter) was palpable in the lower pole of the right thyroid lobe. A partial resection of thyroid including the nodule was performed (Fig. ). Intraoperative frozen biopsy of the intrathyroidal nodule revealed parathyroid hyperplasia (Fig. ). Intraoperative iPTH levels decreased 20 min after the thyrotomy (30 pg/dL). After surgery, the patient's serum Ca and iPTH levels returned to normal, and renal function was well maintained.