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| CASE REPORT |
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| Year : 2019 | Volume
: 14
| Issue : 1 | Page : 47-49 |
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Parathyroid adenoma: Ultrasonography, Doppler, and elastography imaging
Sharvari Shashikant Gulve, Suresh Vasant Phatak
Department of Radiodiagnosis, Jawaharlal Nehru Medical College, Wardha, Maharashtra, India
| Date of Web Publication | 21-May-2019 |
Correspondence Address:
Dr. Sharvari Shashikant Gulve
Department of Radiodiagnosis, Jawaharlal Nehru Medical College, Wardha, Maharashtra
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/jdmimsu.jdmimsu_91_18
Symptomatic primary hyperparathyroidism due to parathyroid adenoma is still prominent in developing countries. We are presenting a case report of a young patient who presented with bone pain and a fracture. When investigated further, a large parathyroid adenoma was seen in the lower pole of the right thyroid gland.
Keywords: Doppler, elastography, parathyroid adenoma, ultrasonography
How to cite this article:
Gulve SS, Phatak SV. Parathyroid adenoma: Ultrasonography, Doppler, and elastography imaging. J Datta Meghe Inst Med Sci Univ 2019;14:47-9 |
| Introduction | |  |
Parathyroid gland was first described in humans by Ivar Viktor Sandstorm. There are four parathyroid glands: two superior parathyroid positioned near the upper pole of the thyroid gland and two inferior parathyroid near the lower pole. Parathyroid glands are too small to be visualized on ultrasonography (USG), that is, of the size 5 mm × 4 mm × 1 mm; but, in parathyroid disease, there is enlargement of the gland which allows for its visualization on USG.[1],[2] Parathyroid hormone (PTH) is the key regulator of calcium metabolism. It maintains the serum calcium level by mobilizing calcium at bone surface. PTH also promotes renal hydroxylation of 25-hydroxyvitamin D, which causes intestinal absorption of calcium and binds to receptors within bone, helping in calcium mobilization and mineralization of organic matrix. Other effects include renal tubular reabsorption of calcium and lowering of serum phosphate level by inducing phosphaturia. The tumor in parathyroid gland causes primary hyperparathyroidism. Low calcium levels causes excessive secretion of parathyroid hormone leading to secondary hyperparathyroidism. Tertiary hyperparathyroidism is due to excessive secretion of parathyroid hormones after prolong duration of secondary hyperparathyroidism and results in increased blood calcium levels.[3] Parathyroid adenoma is part of parathyroid proliferative disorders which consist of parathyroid adenoma, parathyroid hyperplasia, and parathyroid carcinoma.[2] The patient of hyperparathyroidism due to parathyroid adenoma generally presents with bone pain, cystic lesions in bones, nephrocalcinosis, psychiatric, or behavioral problems. Nowadays, the patients complain of fatigability and weakness.[3] This can be confirmed by elevated levels of serum parathormone and calcium.
| Case Report | | |
A 35-year-old female presented with complaints of pain over the right hip and difficulty in walking more on the right lower limb for 2 years. She initially complained of pain in multiple joints including all major joints. Pain was insidious in onset and gradually progressive for 1½ years. There was no history of trauma. On examination, right hip movements are painful. X-ray showed multiple osteolytic lesions in bilateral (B/L) femoral diaphysis and pubic rami and was under evaluation for the same. X-ray of the hand showed terminal tuft resorption in fingers. The patient underwent neck sonography which revealed elongated, heterogeneous partially cystic mass of approximate size 35 mm × 19 mm on the right side at the lower pole of thyroid gland separate from the thyroid tissue [Figure 1]. There is extrathyroidal feeding vessel that enters the parathyroid gland at one of its pole which can be accessed on Colour doppler imaging [Figure 2]. The feeding artery of the adenoma tends to branch around the periphery of the gland and then penetrates deeper resulting in characteristic arc or rim of vascularity. Internal vascularity is also seen in a peripheral distribution [Figure 3] and [Figure 4]. Elastography was also done for the same lesion, which revealed mostly soft colors in the lesion (green and red) with a strain ratio of 0.86 indicating benign nature of the lesion [Figure 4]. PTH was elevated (203.7 IU). Based on these findings, the diagnosis of parathyroid adenoma was made which was later confirmed on histopathology after surgery. The patient showed improvement in her condition after surgery. | Figure 1: Ultrasonography reveals an elongated, heterogeneous cystic mass measuring 35 mm × 19.3 mm
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 | Figure 2: Color Doppler showing feeding vessel arching around the gland before entering it. Internal vascularity is also demonstrated with peripheral distribution
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 | Figure 3: Power Doppler shows the feeding artery arching around the gland and the internal vascularity
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 | Figure 4: Elastography of the region of interest showing mostly soft colors (red and green) and the strain ratio of 0.86, which suggests the benign nature of the lesion
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| Discussion | | |
USG is the first modality in the detection and localization of parathyroid adenomas. As the parathyroid gland enlarges, an abnormal enlarged gland appears hypoechoic and sometimes anechoic compared to adjacent thyroid gland and is located posterior to the thyroid gland.[4] On ultrasonographic grey scale imaging parathyroid adenoma appears as well defined hypoechoic lesion adjacent to hyperechoic thyroid gland and is usually greater than 1 cm in diameter. Hypoechogenicity may be due to compact cellularity, that is, characteristic of adenomas at sectioning. They are generally oval shaped or bean shaped but larger adenomas can be multiloculated. Parathyroid adenomas generally have well-defined margins. Small adenomas are ovoid, but as they enlarge, they become more oblong shaped and are often parallel to the long axis of the neck.[5] Parathyroid adenomas are highly vascular lesions. Color Doppler imaging shows extrathyroidal feeding vessel, which enters the parathyroid gland at one of the poles. The extrathyroidal feeding artery initially branch around the periphery of the gland and then it penetrates deeper resulting in development of arc or rim of vascularity which is characteristic. Internal vascularity is also seen in a peripheral distribution. The color Doppler of thyroid gland shows asymmetrical vascularity that helps in the localization of the underlying adenoma.[5],[6] Color Doppler of parathyroid adenoma is characterized by low resistance waveform.[4] There is increase in vascularity which is readily distinguishable from that of the feeding artery, is helpful for locating adenoma, which can access by using power doppler imaging. The feeding artery that supplies the small adenoma are often generally visualized before the adenoma.[6]
Strain ratio measurement is the semiquantitative method developed to access the lesion. The average strain of the lesion can be calculated by selecting the region of interest encompassing the lesion. As the stiffness increases, the strain ratio increases.[7] Itoh et al. in 2006 gave Tsukuba scoring system of elastography to differentiate benign and malignant masses. A score of 1 indicated even strain for the entire hypoechoic lesion (i.e., the entire lesion was evenly shaded in green). A score of 2 means strain in most of the hypoechoic lesion, with some areas of no strain (i.e., the hypoechoic lesion had a mosaic pattern of green and blue). A score of 3 implies strain at the periphery of the hypoechoic lesion, with sparing of the center of the lesion (i.e., the peripheral part of lesion was green and the central part was blue). A score of 4 shows no strain in the entire hypoechoic lesion (i.e., the entire lesion was blue, but its surrounding area was not included). A score of 5 indicated no strain in the entire hypoechoic lesion or in the surrounding area (i.e., both the entire hypoechoic lesion and its surrounding area were blue). BGR represents typical artifactual three-layered aspect (blue–green–red) encountered with cystic lesions. In strain patterns, score 1, 2, and 3 emphasized benign features, whereas masses with scores of 4 and 5 were considered as malignant.[8] The hypoechoic thyroid nodule and enlarged lymph node is the most common differential diagnosis.[6]
| Conclusion | | |
Parathyroid adenoma is the rare condition observed. It is associated with many complications, and patients may land in acute hyperparathyroidism. Complication may range from fatigue weakness to severe complications such as brown tumor and pathological fracture. The imaging features of parathyroid adenoma on ultrasonography are very characteristic leading to accurate diagnosis. USG scan gives exact location and extension of lesion which helps surgeon in preoperative assessment. Doppler and elastography help further in its diagnosis and management.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
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