Endocrine Abstracts

Parathyroid adenomas (85% of cases of primary hyperparathyroidism) are usually small in size (weigh 70 mg – 1 g). Giant parathyroid adenomas (GPTA) weighing more than 3.5 g are very rare, more common in males, in the 6^th decade of life, generally affect one parathyroid gland, are oxyphilic and ectopic in 50% of cases.

We report the case of a 53-year-old woman presented for asthenia, fatigue, tingling in the arms and legs without other symptoms of hypercalcaemia. Laboratory analysis showed: ionized calcium 6.5 mg/dl (normal: 4.2–5.4 mg/dl), total calcium 13.9 mg/dl (normal: 8.8 to 10.0 mg/dl), hypophosphoremia 2.0 mg/dl (normal: 2.3 to 4.7 mg/dl) and 809 pg/mL intact-parathyroid hormone (normal: 11.0 to 67.0 pg/ml). Calcitonin, thyroxin and thyroid-stimulating hormone levels were normal. Cervical ultrasonography revealed a solid hypoechoic nodule located postero-inferior of the right thyroid lobe with retrosternal extension. An ectopic GPTA localised in para-aortic region of superior mediastinum stretching down to the bifurcation of the trachea was detected using technetium-99m sestamibi scintigraphy and single photon emission computed tomography/computed tomography (SPECT/CT). GPTA measuring 8.5×4×4.5 cm was removed via cervical approach. Histopathology indicated an atypical GPTA with main cells, oncocytic cells, follicular areas, Ki67 < 5% (rarely, in very small areas Ki67 was up to 10%); chromogranin and cytokeratin AE1/3 were positive; carcinoembryonic antigen, thyroid transcription factor1, and thyroglobuline were negative.

The peculiarities of this case: GPTA but poor symptomatology of hypercalcemia and moderately elevated serum calcium levels; ablation of GPTA by cervical incision although mediastinal expansion; mild hungry bone syndrome postoperatively (not correlated with GPTA volume). In conclusion, GPTA is a very rare condition but their size is not an argument in favour of malignancy. Cervical incision should be considered before sternotomy and thoracic/mediastinal approach.