Simultaneous intrathyroidal parathyroid adenomas and multifocal papillary thyroid carcinoma in a patient with kidney transplantation: a case report
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Persistent hyperparathyroidism after kidney transplantation has been associated with adverse outcomes. Parathyroidectomy is the definitive treatment approach, but the success of parathyroidectomy relies on the accurate preoperative localization of the culprit parathyroid lesions. Simultaneous intrathyroidal parathyroid adenomas and multifocal papillary thyroid carcinoma present important diagnostic challenges. Here, we describe a patient with kidney transplantation who underwent successful surgery after being evaluated with functional and structural imaging.
A 53-year-old man presented with potentially malignant multifocal thyroid nodules by ultrasonography 2 years after kidney transplantation. The patient had hypercalcaemia and persistent hyperparathyroidism. Thyroid papillary carcinoma was confirmed in the left thyroid nodules by fine-needle aspiration biopsy. The right superior thyroid hypoechoic nodule was 1.2 cm in size and showed marked uptake of the tracer 99mTcO4-sestamibi during single-photon emission computed tomography/computed tomography (SPECT/CT); additionally, a cystic parathyroid lesion without tracer uptake was present behind the left superior pole of the thyroid. The histological examination demonstrated the coexistence of right intrathyroidal parathyroid adenomas, left cystic parathyroid nodular hyperplasia and multifocal papillary thyroid carcinoma. At the 6-month follow-up, the serum calcium levels were within the normal range, and the patient’s kidney function remained stable.
Simultaneous intrathyroidal parathyroid adenomas and multifocal papillary thyroid carcinoma in a patient with kidney transplantation is a rare clinical scenario. Physicians must be aware that the combination of functional (SPECT/CT) and structural (ultrasonography) imaging is highly successful in diagnosing patients with coexistent intrathyroidal parathyroid adenomas and papillary thyroid carcinoma.
KeywordsIntrathyroidal parathyroid adenomas Hyperparathyroidism Papillary thyroid carcinoma Kidney transplantation
Intrathyroidal parathyroid adenoma
Persistent post-transplant hyperparathyroidism
Single-photon emission computed tomography/computed tomography
Kidney transplantation is an important strategy and the treatment of choice for patients with end-stage renal disease as this method will increase quality of life and improve patient survival . Following kidney transplantation, parathyroid hyperplasia may slowly regress during recovery . However, persistent post-transplant hyperparathyroidism (PT-HPT) is common because monoclonal parathyroid tissue either has a reduced response or lacks the typical response to physiologic regulatory mechanisms of parathyroid secretion and proliferation . PT-HPT puts patients at high risk for bone fractures, mortality and renal graft loss [4, 5]. Surgical excision is considered as this method represents the only definitive cure. The precise preoperative localization of the abnormal parathyroid tissue, especially the identification of ectopic or supernumerary parathyroid tissue, is crucial to a successful surgery . Currently, no consensus exists regarding the universally accepted imaging modalities for preoperative localization. Different imaging modalities have varying strengths and weaknesses depending on the clinical scenario . Ultrasonography can help localize parathyroid disease and assess concomitant thyroid disease. However, ultrasonography has difficulty diagnosing intrathyroidal parathyroid adenoma (IPA) and particularly struggles in the differential diagnosis of thyroid nodules, IPA and papillary thyroid carcinoma . 99mTcO4-sestamibi single-photon emission computed tomography/computed tomography (SPECT/CT) has a high sensitivity (84%) and positive predictive value (95%) and especially improves upon the detection rate of ultrasonography for ectopic tissue, which is likely to be missed by ultrasonography . The combination of structural and functional imaging with ultrasonography and SPEC/CT may increase the localization accuracy and specificity to resolve this problem . Here, we present a very rare case of simultaneous IPA, cystic parathyroid nodular hyperplasia and multifocal papillary thyroid carcinoma in a patient with kidney transplantation.
Results of laboratory values during the surgery and 6-month follow-up
Before kidney transplantation
After kidney transplantation
Thyroid stimulating hormone
Discussion and conclusions
Our report presents multiple challenges with respect to identifying the unique imaging features that clinicians should be aware of while managing patients with simultaneous hyperparathyroidism and thyroid nodules, especially patients with kidney transplantation. PT-HPT can be observed in some patients with successful kidney transplantation. PT-HPT occurs in 45 and 20% of kidney transplantation recipients after 2 years and 5 years, respectively . The main cause of PT-HPT is enlarged and autonomous adenomas with dysregulated metabolic bone mineral parameters, even when the renal function of the allograft recovers to normal . Studies have reported that PT-HPT is associated with an elevated risk of fractures, cardiovascular disease, allograft loss (5%) and mortality (4%) [4, 5, 11, 12]. Treatment for PT-HPT should be individualized, and parathyroidectomy should be considered.
Four orthotopic parathyroid glands are usually located behind the thyroid and originate from the third and fourth pharyngeal pouch. For successful parathyroidectomy, an accurate preoperative localization of the culprit parathyroid tissues is critical. Ectopic parathyroid adenomas occur in approximately 20 and 66% of patients with primary hyperparathyroidism and patients who undergo reoperation, respectively . IPA is rarely observed in certain locations in the parathyroid. The incidence of IPA has been reported to be 1.3–6.7% [13, 14], but the literature has reported that the incidence of parathyroid adenomas located completely within the thyroid is less than 1%, and the most common location is inferior to the thyroid . Some scientists speculate that the primordium of the parathyroid gland was trapped and migrated within the thyroid, thus forming as an intrathyroidal parathyroid gland. Ultrasonography and 99mTcO4-sestamibi SPEC/CT are the most common imaging modalities used to locate abnormal parathyroid glands. Ultrasonography can facilitate an excellent assessment of parathyroid adenomas (sensitivity: 76%, positive predictive value: 93%), but ultrasonography cannot detect ectopic sites, such as mediastinal, retroclavicular and retrooesophageal sites . Ultrasonography is also relatively insensitive in detecting concurrent thyroid nodules and has challenges in identifying IPA . Thyroid nodules occur in the endemic areas of up to 68% of all patients . In total, 3% of patients have occult papillary carcinoma, and the incidence increases with age . The incidence of thyroid papillary carcinoma in kidney transplant recipients is low, some studies evaluated that the incidence of thyroid cancer was 0.22–2.3% [20, 21]. Although the hyperechoic line on the ventral surface of the nodule is an important clue for diagnosing IPA, our patient had no characteristic imaging features . Therefore, further evaluation was required with 99mTcO4-sestamibi SPEC/CT, which has high sensitivity (84%) and positive predictive value (95%) and improves upon the detection rate of ultrasonography for ectopic lesions . In our case, ultrasonography only found one cystic parathyroid nodule without tracer uptake, and the left thyroid nodule was confirmed as papillary carcinoma by FNAB. Focal uptake in the right superior thyroid nodule on SPECT/CT is consistent with IPA due to persistent hyperparathyroidism after kidney transplantation. Some studies report that the combination of ultrasonography and 99mTcO4-sestamibi SPECT can accurately locate IPA [8, 9, 10, 23, 24, 25, 26, 27].
When IPA and multifocal papillary thyroid carcinoma are diagnosed in patients with kidney transplantation, no consensus guidelines exist for the best practices. Therefore, the decisions depend on the individual patient characteristics and the surgeons’ preferences, and the treatment would maintain normal calcium levels and renal function.
To the best of our knowledge, this is the first report of simultaneous IPA and multifocal papillary thyroid carcinoma in a patient with kidney transplantation. Although the precise localization and differential diagnosis of these conditions are challenging, the combination of ultrasonography, SPECT/CT and careful interpretation could help clinicians confirm the presence of IPA and papillary thyroid carcinoma.
JY examined and drafted the manuscript. JZ and WW contributed to interpretation of the clinical data. JB helped to draft the manuscript. MD are corresponding author and organized the study. All authors read and approved the final manuscript.
This work was supported by the Science and Technology Panning Project of Zhejiang Province, China (2017KY061). The funding body had no role in the design, and preparation, writing, review, or approval of the manuscript.
Ethics approval and consent to participate
Consent for publication
Written informed consent to publish has been obtained from the patient for publication of the case report and all images in it.
The authors declare that they have no competing interests.
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