Synchronous parathyroid adenoma and thyroid papillary carcinoma: a case report
© Iakovou et al; licensee BioMed Central Ltd. 2009
Received: 19 October 2009
Accepted: 30 November 2009
Published: 30 November 2009
A 51-year-old female patient presented with atypical chest pain, laryngo-oesophageal reflux, increased levels of serum calcium and parathyroid hormone. Ultrasonography showed a multinodular goiter with a prominent solid nodule in the lower left thyroid lobe and a solid hypoechoic nodule outside this area.
Tc99m-sestamibi parathyroid scintigraphy was performed to investigate a primary hyperparathyroidism, revealing an area with increased uptake in the lower left thyroid lobe and another area with marked uptake lower than this level. Thyroid scintigraphy with 99mTc showed a cold nodule of the left lower pole. FNA of the thyroid nodule was positive for papillary carcinoma later verified by postoperative histopathology.
This case underlines the need for a clinical high index of suspicion for synchronous hyperparathyroidism and thyroid cancer.
A 51-year-old female patient presented with symptoms of atypical chest pain and laryngo-oesophageal reflux. The patient had a past medical history of nephrolithiasis with normal renal function. Blood tests revealed increased levels of serum calcium of 12.8 mg/dL (normal, 9.0-10.6 mg/dL), incrased levels of parathyroid hormone (PTH) at 115 pg/mL (normal, 12-72 pg/mL), and a low serum phosphorus level of 2.4 mg/dL (normal, 2.5-4.5 mg/dL), findings suggestive for primary hyperparathyroidism. Free thyroxine (FT4), triiodothyronine (FT3) and thyroid-stimulating hormone (TSH) levels were within normal limits.
Ultrasonography displayed a multinodular goiter (total thyroid volume was about 43 ml) with a prominent solid nodule in the lower third of the left lobe of the thyroid gland and an additional solid hypoechoic nodule outside the gland but in close relation to the lower pole of the left lobe of it. Multiple endocrine neoplasia (MEN) syndrome was excluded since no blood test no abdomen CT gave evidence of pheochromocytoma existence.
The patient underwent parathyroidectomy and a total thyroidectomy. No palpable cervical lymph nodes were discovered after detailed intraoperative exploration of the region. Histopathology results revealed parathyroid adenoma (1.5 cm greater diameter) in the left lower parathyroid gland and coexistent papillary carcinoma of the left lower lobe of thyroid gland (infiltrating, 2 cm in greater diameter).
The patient's postoperative course was uneventful, normocalcemia was achieved immediately after parathyroidectomy, and she was discharged from the hospital on the third postoperative day. Fifty days later the patient received 100 mCi 131I to ablate any residual thyroid parenchyma followed by treatment with suppressive doses of thyroxine (T4; 175 mg/day).
Primary hyperparathyroidism is a rare condition, however its incidence presents a noticeable increase over the last decades .
An association between hyperparathyroidism and well-differentiated thyroid carcinoma has been reported in many studies. In a retrospective study of 824 patients who had undergone cervical exploration for hyperparathyroidism in which at least a thyroid lobectomy was carried out, thyroid carcinoma was detected in 18 patients (8.6%) with primary hyperparathyroidism .
Burmeister et al additionally compared the incidence of thyroid carcinoma among groups of primary, secondary and tertiary hyperparathyroidism patients and found that the prevalence of thyroid carcinoma in a population of patients undergoing parathyroidectomy for hyperparathyroidism was the same irrespective of whether the patients had primary, secondary or tertiary hyperparathyroidism . They concluded that the detection of thyroid carcinoma at the time of parathyroidectomy is related to risk factors that are probably not associated with hyperparathyroidism. The association between thyroid carcinoma and hyperparathyroidism may be coincidental.
Diagnostic procedure for the preoperative localization of a suspected parathyroid adenoma includes a 99mTc sestamibi scintigraphy. Taillefer et al developed a double-phase imaging procedure with 99mTc sestamibi for the detection and localization of parathyroid adenomas based on the fact that 99mTc sestamibi washes out more rapidly from the thyroid than from abnormal parathyroid tissue . The above procedure improved surgeons' ability to localize parathyroid adenomas preoperatively .
The presence of a parathyroid adenoma is defined as a focal area showing increased 99mTc-sestamibi uptake in projection of the thyroid bed and surrounding areas including mediastinum. This area presents either a relatively progressive increase over time or a fixed uptake persisted on delayed imaging. On the contrary the uptake in the surrounding normal thyroid tissue, progressively decreases over time. The sensitivity of the dual-phase protocol varies and is influenced by numerous factors. These factors are related to the tumour such as tumoral tissue volume, oxyphilic cell content, P-glycoprotein expression, mitochondrial structure or related to the procedure set up such as the dose of radiotracer, the timing of imaging after radiotracer injection, and equipment and settings [5, 6].
However, sestamibi scan may be positive in different benign and malignant thyroid tumours . This is because the tracer is a lipophilic cationic molecule concentrating in cells with different metabolic background with active or passive transport and intramithochondrial sequestration. Thus, ambiguous sestamibi scan images may be observed when parathyroid and thyroid tumours are associated. This underscores the need of an integrated approach using the combination of sestamibi scan with other imaging modalities (e.g. in our case thyroid scintigraphy) in the differential diagnosis of selected cases of primary hyperparathyroidism, especially when associated to multinodular thyroids, and/or after failure of previous parathyroid surgery.
Certainly hyperparathyroidism should not be considered as a high suspicious condition for thyroid cancer; instead, each patient with hyperparathyroidism should be studied including as a possible part of a MEN syndrome while the presence of a non-toxic goiter with suspicious nodule should also be studied, including a FNAB.
Although the incidence of thyroid malignancy in patients with hyperparathyroidism is relatively low, delayed thyroid clearance of 99mTc sestamibi may need to be investigated further. This case underlines the need for a clinical high index of suspicion for synchronous hyperparathyroidism and thyroid cancer. Dual-phase 99mTc sestamibi parathyroid imaging may be useful in detecting thyroid cancer even along with other diagnostic modalities.
Written informed consent was obtained from the patient for publication of this case report and accompanying image. A copy of the written consent is available for review by the Editor-in Chief of this journal.
- Heath H, Hodgson SF, Kennedy MA: Primary hyperparathyroidism. Incidence, morbidity, and potential economic impact in a community. N Engl J Med. 1980, 302: 189-193.View ArticlePubMedGoogle Scholar
- Burmeister LA, Sandberg M, Carty SE, Watson CG: Thyroid carcinoma found at parathyroidectomy: association with primary, secondary, and tertiary hyperparathyroidism. Cancer. 1997, 79: 1611-1616. 10.1002/(SICI)1097-0142(19970415)79:8<1611::AID-CNCR26>3.0.CO;2-#.View ArticlePubMedGoogle Scholar
- Taillefer R, Boucher Y, Potvin C, Lambert R: Detection and localization of parathyroid adenomas in patients with hyperparathyroidism using a single radionuclide imaging procedure with technetium-99m-sestamibi (double-phase study). Journal of Nuclear Medicine. 1992, 33: 1801-1807.PubMedGoogle Scholar
- Palestro CJ, Tomas MB, Tronco GG: Radionuclide imaging of the parathyroid glands. Semin Nucl Med. 2005, 35: 266-276. 10.1053/j.semnuclmed.2005.06.001.View ArticlePubMedGoogle Scholar
- Gupta Y, Ahmed R, Happerfield L, Pinder SE, Balan KK, Wishart GC: P-glycoprotein expression is associated with sestamibi washout in primary hyperparathyroidism. Br J Surg. 2007, 94: 1491-1495. 10.1002/bjs.5882.View ArticlePubMedGoogle Scholar
- Ballinger JR, Cooper MS: Increasing the radiochemical purity of 99mTc-sestamibi commercial preparations results in improved sensitivity of dual-phase planar parathyroid scintigraphy. Nucl Med Commun. 2006, 27: 543-544. 10.1097/00006231-200606000-00011.View ArticlePubMedGoogle Scholar
- 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: 330-333. 10.1007/BF00169809.View ArticlePubMedGoogle Scholar
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