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I find it difficult/impossible to detect the isoechoic lesion or the echogenic rim in figure 3a. Response: We wanted to highlight how difficult it could be to see an ...
Insights into Imaging Atypical ultrasound features of parathyroid tumours may bear a relationship to their clinical and biochemical presentation. --Manuscript Draft-Manuscript Number:

INII-D-13-00109R1

Full Title:

Atypical ultrasound features of parathyroid tumours may bear a relationship to their clinical and biochemical presentation.

Article Type:

Original Article

Corresponding Author:

Anuradha Chandramohan, DMRD, MD, DNB, FRCR Christian Medical College Vellore, Tamil Nadu INDIA

Corresponding Author Secondary Information: Corresponding Author's Institution:

Christian Medical College

Corresponding Author's Secondary Institution: First Author:

Anuradha Chandramohan, DMRD, MD, DNB, FRCR

First Author Secondary Information: Order of Authors:

Anuradha Chandramohan, DMRD, MD, DNB, FRCR Kirthi Sathyakumar, MBBS Reetu Amrita John, DMRD, MD Marie Therese Manipadam, MD Deepak Abraham, MS, PhD Thomas V Paul, MD, DNB Nihal Thomas, MD, MNAMS DNB(Endo)FRACP(Endo) FRC P(Edin) MJ Paul, MS

Order of Authors Secondary Information: Abstract:

Objectives: To describe atypical ultrasound features of parathyroid lesions and correlate with clinical presentation and histopathology. Materials and methods: Retrospective review of 264 patients with primary hyperparathyroidism who underwent ultrasound imaging prior to parathyroidectomy was performed. Patients with atypical ultrasound findings (n=26) were identified; imaging findings were correlated with clinical presentation and histopathology. Results: Twenty one(80%) lesions were adenomas, two(8%) were adenomas with cellular atypia and three(11.5%) were carcinomas. Seventeen(65%) lesions showed cystic change; 5(19%) of them had >50% cystic change. These lesions were adenomas. Cystic degeneration had significant positive correlation with lesion size and PTH level, but cystic adenomas negatively correlated with lesion weight. Six(23%) lesions were isoechoic and one(4%) was hyperechoic; histology predominantly revealed haemorrhage, hyalinisation and fibrosis, one lesion showed fat deposition and another had multiple granulomas within adenoma. Twenty(83%) lesions had heterogeneous echotexture and showed combinations of acinar dilatation, necrosis, haemorrhage and fibrosis. Heterogeneous lesions tended to be significantly larger, heavier and had higher PTH levels. Four(15%) lesions had calcifications. Scintigraphy was concordant in 22(96%), n=23. One scintigraphy negative lesion was a cystic parathyroid adenoma. Conclusion: Atypical ultrasound features of parathyroid lesions pose a diagnostic Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation

challenge. Awareness of these features would help improve lesion detection. Response to Reviewers:

Author’s response to comments of the reviewers Ref.: Ms. No. INII-D-13-00109 entitled "Atypical ultrasound features of parathyroid tumours may be related to their clinical and biochemical presentation", submitted to Insights into Imaging Dear Editor, Thank you very much for the review and valuable suggestions. Following is the author’s response to the reviewer’s comments. Reviewer #1: 1.3% of the group's cases with typical US features for adenoma are carcinomas 11% (n=3) of cases with non-typical findings are carcinomas, 89% are adenomas Cystic change was correlated with PTH levels. All cystic lesions were adenomas Iso/hyperechogenicity not correlated with histology - I infer this, no statement made in text Heterogeneity seen in carcinomas, adenomas and adenomas with atypia Calcification seen in adenomas and one carcinoma. Cysts weigh less than solid masses. Response: All iso and hyperechoic lesions were adenomas and we have added this information to the manuscript. 2. The data show substantial overlap of histology for the non-typical US features and are not helpful in making a confident preoperative diagnosis of malignancy. Limited data are presented on the statistical association between the features described and the histology, perhaps because they were non significant? The statistical correlation between lesion weight and cystic change seems of limited clinical relevance to me. Response: We agree with the reviewer’s comments. The purpose of this study is not to be able to make an imaging diagnosis of parathyroid carcinoma, but to be able to correctly diagnose a parathyroid lesion in spite of its atypical imaging features. It is important for clinical colleagues to realise that the prevalence of parathyroid carcinoma is higher among lesions with atypical features. That is what we wanted to convey. 3. There were 25 patients with 26 lesions; the paragraph on Tc-99m Sestamibi performance seems to refer to 23 or 25 patients or possibly 25 lesions. It is not clear and should be edited. Response: There were 25 patients with 26 lesions in our study. In the paragraph on Tc99m Sestamibi performance our statement “Tc-99 Sestamibi scintigraphy was concordant in 22 (95.7%), n=23.” meant that of the 25 patients only 23 had scintigraphy and out of them 22 were concordant. 4. Patient chracteristics paragraph 1 notes a PTH level of 11.63.24 pg/ml, a decimal point is misplaced. Response: Corrected

Reviewer #2: Thanks for the kind review and the valuable suggestions. Author’s response: Teaching points: Reviewer has suggested it to be shortened. Response: as suggested was shortened Material and Methods: 5. Reviewer was concerned about the ultrasound machines which were used. Response: List of ultrasound machines and probe details have been added to the manuscript in the form of a table (Table 1) 6. How many original examiners performed the ultrasound examinations? Response: Being a large teaching hospital, ultrasound was performed by many radiologists over the last 12 years including the three radiologists who are authors of this study. 7. How standardized was the documentation of the examination, so that it could Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation

reliably be retrospectively reviewed? Response: Since PACS and clinical workstation has been there from 1999, documentation has been very reliable. Results: 10. Table 1 gives clinical information; it might be interesting to add the mean size of the lesions in this section. Response: Size of the lesion is mentioned in the table (Table 2). References: 12. reference 6 lacks the year of publication. Response: Corrected 14. the radiological papers are quite out dated; it would be desirable to add some of the current literature, e.g.: Johnson NA, Yip L, Tublin ME. Cystic parathyroid adenoma: sonographic features and correlation with 99mTc-sestamibi SPECT findings. AJR 2010;195(6):1385-90. doi: 10.2214/AJR.10.4472. Response: The reference suggested by the reviewer is already cited: ref 6 in the manuscript. Figure legends: 16. there seems to be more devotion to describe the histological features than the ultrasound characteristics Response: effort was taken to keep the pathology description to the bare essential. Figures 19. I find it difficult/impossible to detect the isoechoic lesion or the echogenic rim in figure 3a Response: We wanted to highlight how difficult it could be to see an isoechoic lesion. Thus the need for meticulous scan technique and knowledge that parathyroid adenomas can be isoechoic. 20. Should figure 9 be 8e (same patient?)? Response: Fig 8 and 9 belongs to the same patient. As suggested Fig 9 has been relabelled as Figure 8e.

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Title Page

Article type: Original article Title of the article: Atypical morphology of parathyroid tumours may be related to their clinical and biochemical presentation Running title: Atypical ultrasound features of parathyroid lesions

Authors: 1. Anuradha Chandramohan, MD, DNB, FRCR Assistant Professor of Radiology Department of Radiology Christian Medical College Vellore Tamil Nadu India – 632004. Phone numbers: 0416-2283012 Mobile: +919443449726 [email protected]

2. Kirthi Sathyakumar, MBBS PG trainee (MD Radiology) Department of Radiology Christian Medical College Vellore Tamil Nadu India – 632004 Phone numbers: 0416-2283012 Mobile: +918489014491 [email protected]

3. Reetu Amrita John, DMRD, MD Assistant Professor of Radiology Department of Radiology Christian Medical College Vellore Tamil Nadu India – 632004. Phone numbers: 0416-2283012 [email protected]

4. Marie Therese Manipadam, MD Professor of Pathology Department of Pathology

Christian Medical College Vellore Tamil Nadu India – 632004 Phone: 0416 2283124 [email protected]

5. Deepak Abraham, MS, PhD Professor of Endocrine surgery Department of Endocrine surgery Christian Medical College, Vellore. Tamil Nadu India – 632004. Phone numbers: 0416-2282609 Mobile: +918903310235 [email protected]

6. Thomas V Paul, MD, DNB Professor of Endocrinology Department of Endocrinology Christian Medical College, Vellore. Tamil Nadu India – 632004. Phone numbers: 0416-2283571 [email protected]

7. Nihal Thomas, MD, MNAMS DNB(Endo)FRACP(Endo) FRC P(Edin) Professor and head of Endocrinology Department of Endocrinology Christian Medical College, Vellore. Tamil Nadu India – 632004. Phone numbers: 0416-2282694 [email protected]

8. MJ Paul, MS Professor and head of Endocrine surgery Department of Endocrine surgery Christian Medical College, Vellore. Tamil Nadu India – 632004. Phone numbers: 0416-2282609 Mobile: +919486660601 [email protected]

Department(s) and institution(s) : Department of radiology, pathology, endocrinology and endocrine surgery, Christian Medical College, Vellore.

Corresponding Author: Anuradha Chandramohan Department of Radiology, Christian Medical College, Vellore. Tamil Nadu – 632002. Phone numbers: 0416-2283012 Mobile: +919443449726 E-mail address: [email protected]

Revised manuscript Click here to view linked References

Article type: Original article 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

Title of the article: Atypical ultrasound features of parathyroid tumours may bear a relationship to their clinical and biochemical presentation. Running title: Atypical ultrasound features of parathyroid lesions

Abstract Objectives: To describe atypical ultrasound features of parathyroid lesions and correlate with clinical presentation and histopathology. Materials and methods: Retrospective review of 264 patients with primary hyperparathyroidism who underwent ultrasound imaging prior to parathyroidectomy was performed. Patients with atypical ultrasound findings (n=26) were identified; imaging findings were correlated with clinical presentation and histopathology. Results: Twenty one (80%) lesions were adenomas, two (8%) were adenomas with cellular atypia and three (11.5%) were carcinomas. Seventeen (65%) lesions showed cystic change; 5 (19%) of them had >50% cystic change. These lesions were adenomas with cystic degeneration. Cystic degeneration had significant positive correlation with lesion size and PTH level, but cystic adenomas negatively correlated with lesion weight. Six (23%) lesions were isoechoic and one (4%) was hyperechoic; histology predominantly revealed haemorrhage, hyalinisation and fibrosis, one lesion showed fat deposition and another had multiple granulomas within adenoma. Twenty(83%) lesions had heterogeneous echotexture and showed combinations of acinar dilatation, necrosis, haemorrhage and fibrosis. Heterogeneous lesions tended to be significantly larger, heavier and were

associated with higher PTH levels. Four (15%) lesions had calcifications. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

Scintigraphy was concordant in 22 (96%), n=23. One scintigraphy negative lesion was a cystic parathyroid adenoma. Conclusion: Atypical ultrasound features of parathyroid lesions pose a diagnostic challenge. Awareness of these features would help improve lesion detection.

Key-words: atypical features; parathyroid; ultrasound; histopathology Teaching points: 1. Cystic change is significantly related to the size, weight and measured parathyroid hormone levels. 2. Cystic change in parathyroid tumours had a slightly higher risk of malignancy. 3. Heterogeneous parathyroid adenomas are larger in size, heavier and had higher PTH levels. 4. Awareness of atypical ultrasound features will improve preoperative clinical prediction.

Introduction 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

Primary hyperparathyroidism is a common endocrine disorder which can result from adenoma or hyperplasia of the parathyroid gland. In 80-90% of cases it occurs as a result of benign adenoma of the parathyroid gland.(1) Sonography and Tc-99 Sestamibi scintigraphy are the imaging modalities of choice in arriving at a diagnosis. (2, 3) Surgical management is most common and provides symptomatic cure as well as biochemical normalization. Ultrasonography is a convenient and inexpensive imaging modality in the evaluation of the thyroid and parathyroid glands with a sensitivity and specificity of 98% and 88%.(4) The grey scale appearances and Doppler features favouring a diagnosis of parathyroid adenoma are well described. The classical imaging features on grey scale include oval or lobulated extra-thyroidal hypoechoic lesions with a well defined margin. On colour Doppler these lesions are very vascular and typically show peripheral vascular arc and prominent polar feeding vessel arising from the branches of inferior thyroidal artery. Other features include vascular asymmetry of the thyroid gland on the side of the lesion and hyperechoic capsule.(3-5) However, there is little literature on atypical ultrasound features of parathyroid lesions, their prevalence and relevance while evaluating parathyroid lesions. The atypical features so far described in literature include purely cystic parathyroid adenomas(6) reported in 4% of all adenomas(7), cystic degeneration in solid adenomas, giant adenomas, inhomogeneous, multi-lobulated and calcified parathyroid tumours.(7, 8)

The purpose of this study was to describe the atypical ultrasound features of 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

parathyroid lesions, to study how it correlates with Tc-99 Sestamibi scintigraphy and histopathology and clinical parameters.

Materials and methods This retrospective study was conducted by Departments of radiology, pathology and endocrinology and endocrine Surgery of a 2800 bedded tertiary care teaching hospital in India on patients with parathyroid ultrasound showing atypical findings. Informed consent was waived with IRB approval. A comprehensive list of all patients who underwent surgery for primary hyperparathyroidism between the years 2000September 2012 was obtained from the Department of Endocrine Surgery database. Ultrasound images and reports of all the patients were reviewed from PACS (Picture Archiving and Communication System) by three radiologists. Images were interpreted by predetermined criteria. Patients with classical ultrasound features such as hypoechoic, well defined, solid lesion with homogenous echotexture, thin echogenic rim and polar extra-thyroidal feeding artery were excluded. Those patients with negative parathyroid ultrasonography were also excluded. Iso- or hyperechogenicity, heterogeneous echotexture with cystic change, purely cystic lesions and presence of calcification were considered atypical findings on parathyroid ultrasound. Criteria for cystic adenoma included a predominantly anechoic lesion with posterior acoustic enhancement. Cystic degeneration was described when there was a solid lesion with one or more anechoic areas within. Degree of cystic change was assessed on ultrasound images. An inhomogeneous echotexture was defined by the presence of hypoechoic areas mixed with areas of hyper-echogenicity. Lab results such as pre-operative and post-operative serum

calcium and parathyroid hormone levels, Tc-99 Sestamibi scintigraphy, intra1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

operative findings, histopathology reports of these patients were reviewed from clinical workstation.

Statistical analysis Statistical analysis was done using IBM SPSS Analytics 16.0 software (Chicago, Ill., USA). To assess factors associated with atypical ultrasound findings, Fisher’s exact test and chi-squared test were performed to analyse categorical data; independent sample T-test was performed to analyse continuous data. Bivariate correlation analysis was performed to correlate the atypical ultrasound finding with biochemical, clinical parameters, pathology and Tc-99 Sestamibi scintigraphy findings. A p-value of less than 0.05 was considered as statistically significant.

Results Patient characteristics: Out of 296 patients who underwent parathyroidectomy for primary hyperparathyroidism at our institution between 2000-Sep 2012, 264 patients had ultrasound for preoperative localisation of abnormal parathyroid glands. A total of 25 patients (10 male and 15 female patients; mean age of 47.8 (range of 21-66) years) had 26 parathyroid lesions with atypical findings on ultrasonography. Mean (± Standard deviation (SD)) of duration of illness in these patients was 40.3 ± 65.2 months (range of 1 month to 22 years). Mean (± SD) of serum calcium level just prior to surgery was 12.3 ± 1.02 mg/dl (range of 10.1 – 14.5 mg/dL, n=25); lab reference

range of 8.3 - 10.4 mg/dL. Mean (± SD) of serum albumin was 4.3 ± 0.6 g% (range 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

of 2.5 – 5.1 g %); lab reference range of 3.5 – 5 g %. Mean (± SD) of serum corrected calcium was 11.97 ± 1.12 mg/dL (range of 9.8 – 14.7 mg/dL, n=25). Mean (± SD) of serum PTH level was 1163.24 ± 760.67 pg/ml, (range of 191 – 2500 pg/ml, n=24); lab reference range of 8 – 74 pg/ml. Mean (± SD) of follow up calcium levels after surgery was 8.57 ± 1.02 mg/dl (range of 5.8 - 10.3 mg/dl, n=25). Table 1 summarises the patient characteristics. Parathyroid lesion characteristics: Of the 26 parathyroid lesions with atypical ultrasound findings, 21 (80.7%) were parathyroid adenomas, two (7.7%) were parathyroid adenoma with cellular atypia and three (11.5%) were parathyroid carcinoma. Mean length (± SD) and weight of the lesion was 32.35 (± 12.4) mm and 697 mg (range 50-2500 mg) respectively. There was no significant difference in the mean length (p=0.071) and weight (p=0.815) of adenomas and carcinomas. Though preoperative mean (± SD) serum calcium levels were slightly higher in patients with parathyroid carcinoma (14.1 ± 0.64 mg/dl) compared to adenoma (12.1 ± 0.93 mg/dl), p=0.007 there was no difference in the levels of parathyroid hormone, p=0.239. Ultrasound features and correlation with histopathology and clinical presentation: There were equal number of lesions in the left and right. Sixteen (61.5%) were inferior parathyroid lesions and 10 (39.5%) were superior. Six (23.1%) lesions were round; 15 (57.7%) were oval and five (19.2%) were elongated. Of the 26 lesions with atypical ultrasound features, 17 (65.4%) lesions showed cystic changes; six (23.1%) lesions were isoechoic; one (3.8%) lesion was hyperechoic; one (3.8%) lesion had mixed echogenecity with hypoechoic and hyperechoic components; 20 (83.3%)

lesions had heterogeneous echotexture and calcification was seen in four (15.3%) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

lesions. There was no association between the shape of the lesion, echotexture, echogenicity and cystic changes within the lesions. There was no association between the shape of the lesion and the histopathological type of the parathyroid lesion (chi square = 2.487, p=0.288). Lesions with cystic change: Out of 17 lesions with cystic change, there were seven superior, 10 inferior; nine right and eight left lesions. The degree of cystic change was less than 10% in 6 (35.3%), 10-50% in 6 (35.2%); 50-75% in 3 (17.6%) and greater than 75% in 2 (11.8%) lesions. There was a significant positive correlation between the presence of cystic degeneration and serum PTH level (r=0.422, p=0.04). However, there was no significant correlation between the duration of disease and the presence of cystic degeneration (p=0.493). There was a significant positive correlation between presence of cystic degeneration and length of the lesion (r=0.416, p=0.035). Lesions with greater than 50% cystic change were labelled as cystic parathyroid lesions. There were 5 (19.2%) cystic parathyroid lesions and all were adenomas, three were from the superior parathyroid gland and two were from inferior parathyroid gland. Four (19.2%) of the cystic adenomas were anechoic on ultrasound and showed predominant cystic change and acinar dilatation on histology (Fig 1). One cystic lesion had fine cob web like internal septations and internal

echoes and was a parathyroid adenoma with haemorrhagic and cystic degeneration 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

on histology (Fig 2). Cystic parathyroid adenomas were equally distributed among both gender (chi square = 0.891, p=0.345). There was significant negative correlation between the cystic parathyroid adenomas and weight of the lesion (r=-0.492, p = 0.038). The length (p=0.606) and weight (p=0.209) of cystic parathyroid adenomas did not differ from other parathyroid adenomas. Iso or hyperechogenicity: Five isoechoic lesions and one hyperechoic lesion were all adenomas and showed evidence of haemorrhage, hyalinisation and fibrosis on histology. One isoechoic lesion was an adenoma and had extensive fat deposition on histology (Fig 3). One (3.8%) lesion which had both hypoechoic and hyperechoic components showed evidence of granulomas interspersed between oncocytic cells in a right inferior parathyroid adenoma (Fig 4). There were no significant neck nodes or evidence of pulmonary tuberculosis in this patient. There was no association between the perception of echogenic rim/ capsule around the lesion and echogenicity (chi square = 1.426, p=0.231). Heterogeneous echotexture: Two parathyroid carcinomas (Fig 5), two adenomas with cellular atypia and sixteen parathyroid adenomas (Fig 6) were heterogeneous in appearance. Lesions with heterogeneous echotexture on ultrasound showed combinations of acinar dilatation, necrosis, haemorrhage and fibrosis on histology. One of them also showed fat deposition.

Echogenic rim around the lesion could be seen in 19 (76%) and could not be seen in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

6 (24%). There was no association between the perception of echogenic rim/ capsule around the lesion and echotexture (chi square = 3.070, p=0.381). There was significant difference between the weight of homogenous (225 ± 35 mg) and heterogeneous (802.7 ± 553.4 mg) lesions, p=0.001 with a tendency for larger lesions to be heterogeneous in echotexture. There was significant positive correlation between the heterogeneous echotexture and serum PTH level (r=0.450, p=0.036); length of the lesion (r=0.566, p=0.004); weight of the lesion (r=0.488, p=0.047). There was no correlation between the duration of disease and echotexture of the lesion (p=0.581). Calcification (Fig 7): Of the four lesions with calcification three were parathyroid adenomas and one was a parathyroid carcinoma. Presence of calcification did not affect the visibility of the echogenic capsule, chi square = 1.077, p=0.299. Performance of Tc-99m Sestamibi scintigraphy: Tc-99 Sestamibi scintigraphy was concordant in 22 (95.7%), n=23. Scintigraphy was discordant in one patient (4.3%) who had double adenoma in both the inferior parathyroid glands. The left inferior cystic parathyroid adenoma which measured 10 x 4 mm and weighed 50 mg was not seen on Tc-99 Sestamibi scintigraphy (Fig 8). This lesion was one of two lesions with > 75% cystic change. Histopathology showed acinar dilatation and haemorrhage in this lesion (Fig 9). Surgery and outcome:

Fifteen (57.7%) patients had focussed parathyroid surgery and 11 (43.2%) had 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

cervical exploration. All the operations in this group were successful in curing hyperparathyroidism. There was no record of rupture during surgery for the cystic lesions. Eleven patients developed hypocalcaemia. Nine required correction with intravenous calcium and rest of them had transient hypocalcaemia. Of the nine patients with symptomatic hypocalcaemia eight patients had large parathyroid lesions with cystic degeneration and their length ranged from 3.5 to 6 cm.There was significant association between post operative symptomatic hypocalcemia and presence of cystic degeneration (p=0.004).

Discussion: In our series approximately 10% of patients who underwent ultrasound for primary hyperparathyroidism had atypical ultrasound features in parathyroid lesions. Parathyroid carcinomas constituted 11.5% of lesions with atypical ultrasound findings in our series while they constitute