Toxic thyroid adenoma with hypercalcemia mimicking an intra-thyroidal parathyroid adenoma

Document Type : Case report


Department of Nuclear Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India


Hypercalcemia is a clinical condition characterized by elevated circulating serum calcium levels either due to raised parathyroid hormone in hyperparathyroidism or due to secondary causes of hypercalcemia without elevated parathyroid hormone levels. However, hyperthyroidism may occasionally present with incidentally detected hypercalcemia. We present a case of a 53-year-old woman with a previous history of an underlying thyroid disorder, now presented with features of hypercalcemia and mildly elevated parathyroid hormone levels. Her ultrasonography of the neck was suggestive of an intra-thyroidal parathyroid adenoma and it was localized as a tracer avid lesion within the thyroid gland on dual-phase 99mTc-sestamibi planar scintigraphy with single photon emission computed tomography/ computed tomography (SPECT/CT). However, a subsequent thyroid profile followed by 99mTc- pertechnetate thyroid scintigraphy showed a hot nodule in the thyroid gland which changed the diagnosis to a toxic thyroid adenoma. She was treated with radioactive iodine ablation and thyrotoxicosis resolved and the serum calcium levels normalized on her follow-up. 


  1. Ross DS, Burch HB, Cooper DS, Greenlee MC, Laurberg P, Maia AL, et al. 2016 American Thyroid Association Guidelines for Diagnosis and Management of Hyperthyroidism and Other Causes of Thyrotoxicosis. Thyroid. 2016; 26(10):1343–421.
  2. Liu J, Tang X, Cheng J, Yang X, Wang Y. Persistent arthralgia, vomiting and hyper calcemia as the initial manifestations of hyperthyroidism: A case report. Mol Clin Oncol. 2017; 6(2):258–60.
  3. Baxter JD, Bondy PK. Hypercalcemia of thyrotoxicosis. Ann Intern Med. 1966; 65 (3): 429-42.
  4. Cheung K, Wang TS, Farrokhyar F, Roman SA, Sosa JA. A meta-analysis of preoperative localization techniques for patients with primary hyperparathyroidism. Ann Surg Oncol. 2012; 19(2):577–83.
  5. Palestro CJ, Tomas MB, Tronco GG. Radionuclide Imaging of the Parathyroid Semin Nucl Med. 2005; 35(4):266–76.
  6. Melloul M, Paz A, Koren R, Cytron S, Feinmesser R, Gal R. 99mTc-MIBI scintigraphy of parathyroid adenomas and its relation to tumour size and oxyphil cell abundance. Eur J Nucl Med. 2001; 28(2):209–13.
  7. Sathekge MM, Mageza RB, Muthuphei MN, Modiba MCM, Clauss RC. Evaluation of thyroid nodules with technetium-99m MIBI and technetium-99m pertechnetate. Head Neck. 2001; 23(4):305–10.
  8. Földes I, Lévay A, Stotz G. Comparative scanning of thyroid nodules with technetium-99m pertechnetate and technetium-99m methoxyisobutylisonitrile. Eur J Nucl Med. 1993; 20(4):330-3.