Primary hyperparathyroidism due to atypical parathyroid adenoma presenting with peroneus brevis tendon rupture

J. Endocrinol. Invest. 30: 442-444, 2007 ©2007, Editrice Kurtis.

lETTER TO THE EDITOR

Primary hyperparathyroidism due to atypical parathyroid adenoma presenting with peroneus brevis tendon rupture Primary hyperparathyroidism (PHPT) as a major cause of hypercalcemia is caused by excessive and incompletely regulated secretion of PTH from one or more of the four parathyroid glands. It contributes to the development of several conditions such as kidney stones, left ventricular hypertrophy, arrhytmias (1, 2) and skeletal manifestations such as osteoporosis, Brown tumor and, less frequently, tendon ruptures (3, 4). Atypical parathyroid adenomas are rare lesions. They show some features of parathyroid carcinomas but lack essential characteristics such as metastasis or vascular invasion. Stojadinovic et al. demonstrated that in their series 8 out of 73 patients with parathyroid neoplasms were diagnosed as atypical parathyroid adenomas (5). In our experience we have had a patient with PHPT due to atypical parathyroid adenoma presenting with spontaneous peroneus brevis tendon rupture. The patient was a 26-yrold woman and she was referrred to our hospital with incidentally determined high serum calcium level (11.2 mg/dl) on routine laboratory investigation. She was totally asymptomatic. The personal history of the patient was not remarkable except for a non-traumatic partial rupture of peroneus brevis tendon 2 months before her admission. She did not have any medications and she did not smoke or consume alcohol. Physical examination was normal. At presentation, complete blood count, liver and renal function tests, thyroid function tests and serum potassium and sodium levels were normal. She had hypercalcemia (11.7 mg/dl) and parathormone level was elevated (1465 pg/ ml). Bone metabolism parameters at admission are shown in the table. Parathyroid ultrasound showed a low-echogenic mass about 20x24x32 mm at the posteroinferior pole of the left thyroid gland. Technetium-99m-sestamibi scan revealed activity in the same area. In Dual x-ray absorptiometry (DEXA) examination, spinal measure-

ments yielded an adult T-score of –3.31 and an age-matched Z-score of –3.25, showing the presence of osteoporosis. Bone mineral density (BMD) was found to be 0.683 gr/cm2. Hip measurements were consistent with osteopenia (T-score and Zscore –1.54) with BMD of 0.791 gr/cm2. Abdominopelvic ultrasonography and chest radiography revealed normal findings. The possibilty of the existence of multiple endocrine neoplasia (MEN) syndromes for this patient was eliminated as she did not have pancreatic, adrenal or thyroid lesions. The calcitonin level was not high and she did not have any clinical findings consistent with acromegaly or insulinoma. As the adenoma was inseparable from thyroid lobe, partial thyroidectomy with left inferior parathyroidectomy was performed. The pathologic diagnosis was atypical parathyroid adenoma. The history of spontaneous peroneus brevis tendon rupture was thought to be associated with primary hyperparathyroidism. The magnetic resonance image of the partial rupture at the right peroneus brevis tendon is shown in Figure 1. The patient has been in good health since the operation. Bone metabolism parameters at discharge are demonstrated in Table 1.

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Fig. 1 - Sagittal magnetic resonance image of the partial peroneus brevis tendon rupture.

Accepted November 2, 2006.

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S. Yener, A. Saklamaz, T. Demir, et al.

J. Endocrinol. Invest. 30: 442-444, 2007 ©2007, Editrice Kurtis.

Table 1 - Laboratory parameters on admission and after the operation. Ca (mg/dl)

Alb (gr/dl)

P (mg/dl)

ALP (U/l)

PTH (pg/ml)

25OH-D (ng/ml)

24-h UCE (mg)

8.2-10

3.5-5.0

2.7- 4.5

34-240

12-72

7.6-75

100-300

Admission

11.2 11.7

4.4 3.9

1.6 1.8

499 553

1465 1664 1205

46

380 299

Discharge

8.7

4.5

4.3

Normal

Calcitonin (pg/ml)

2

27

Ca: Calcium; Alb: Albumin; P: Phosphorus; ALP: alkaline phosphatase; PTH: parathormone; 25OH-D: 25 hydroxy vitamine D; UCE: urinary calcium excretion.

Besides systemic problems like reduction of BMD, nephrolithiasis, hypertension, and left ventricule hypertrophy, patients with primary hyperparathyroidism may have complaints of muscular weakness, easy muscle fatigability and tiredness, which are related to reduction of musculer performance (6). Hyperparathyroidism has been reported to predominantly affect the proximal lower extremity muscles. Several studies have focused on muscle function in primer hyperparathyroidism patients after parathyroidectomy. An improvement in muscle function has been reported in nearly all investigations (7). Deutch et al. showed that women with primary hyperparathyroidism increase knee extension force after parathyroidectomy (6). Non-traumatic tendon ruptures are rare and usually associated with systemic diseases. A review of the literature about spontaneous bilateral patellar tendon ruptures up to 1999 revealed a total of 38 cases. In 26 of the cases the condition was associated with systemic diseases like systemic lupus erythematosus, rheumatoid arthritis, chronic renal failure and primary hyperparathyroidism (8). Tendon ruptures may complicate the course of primary hyperpara­thyroidism. Chen et al. reported bilateral patellar tendon rupture and recently Modrego and Molina reported bilateral quadriceps tendon rupture due to primary hyperparathyroidism (9). Our patient’s unilateral tendon rupture differs from previous cases which presented with bilateral ruptures. A possible explanation for this difference might be the short duration between the diagnosis of primary hyperparathyroidism and the tendon rupture for our patient. If the diagnosis had been delayed the rupture might have become bilateral. As the patient had no history of tendon laxity, previous traumatic injury or any condition associated with tendon fragility such as systemic diseases, history of chronic steroid therapy, rheumatoid arthritis, gout, chronic renal failure, hyperlipidemia, syphilis, gonorrhea and tumors, there was no doubt

about the spontaneous and non-traumatic presentation of the tendon rupture. Rupture of peroneus brevis tendon due to systemic disease is not a frequent condition. De Yoe et al. reported a patient with peroneus brevis tendon rupture with tophaceous gout infiltration (10). Our patient is the first in the literature presenting with spontaneous peroneus brevis tendon rupture due to primary hyperpara­thyroidism. In hyperparathyroidism, it has been proposed that depolymerization of glycoproteins by excessive parathyroid hormone weakens the bone and tendon matrix (11). It has also been suggested that increased osteoclastic cortical bone resorption at the tendon insertion site, due to hyperparathyroidism, may result in repeated minor avulsion fractures of the bone cortex, ultimately leading to scarring and weakening of the tendon attachment site and culminating in its complete rupture (12, 13). This is also the first patient with primary hyperparathyroidism in the literature presenting with tendon rupture due to atypical para­thyroid adenoma. Atypical parathyroid adenomas are not frequently diagnosed as parathyroid neoplasms and there are difficulites in predicting their behavior. Their most important pathological features are trabecular growth, fibrous bands, nuclear polymorphism and no/low rate of mitosis. Furthermore, they are not presented with vascular, perineural and soft tissue invasion. In other words, they share some features with parathyroid carcinomas without the unequivocal properties of malignancy (5). The pathological examination of the patient’s parathyroid lesion was consistent with atypical parathyroid adenoma with the presence of nuclear polymorphism, fibrous bands, 1 mitosis in 40 high power field. There was no capsular or vascular invasion. Ki-67 staining revealed the presence of low proliferation index. Physicians must be aware of the muscular complications of primary hyperparathyroidism. Prolonged hyperparathyroidism and hypercalcemia may cause

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Tendon rupture due to parathyroid adenoma

J. Endocrinol. Invest. 30: 442-444, 2007 ©2007, Editrice Kurtis.

morbidity for these patients and early diagnosis and treatment can prevent complications.

4. Silverberg SJ, Shane E, de la Cruz L, et al. Skeletal disease in primary hyperparathyroidism. J Bone Miner Res 1989, 4: 283-91. 5. Stojadinovic A, Hoos A, Nissan A, et al. Parathyroid neoplasms: clinical, histopathological, and tissue microarraybased molecular analysis. Hum Pathol 2003, 34: 54-64.

S. Yener1, A. Saklamaz1, T. Demir1, L. Kebapcilar1, F. Bayraktar1, S. Canda2, and S. Yesil1

6. Deutch SR, Jensen MB, Christiansen PM, Hessov I. Muscular performance and fatigue in primary hyperparathyroidism. World J Surg 2000, 24: 102-7.

1Division of Endocrinology and Metabolism,

7. Patten BM, Bilezikian JP, Mallette LE, Prince A, Engel WK, Aurbach GD. Neuromuscular disease in primary hyperpara­ thyroidism. Ann Intern Med 1974, 80: 182-93.

Department of Internal Medicine;

2Department of Pathology, Dokuz Eylul

University, Izmir, Turkey

8. Chen CH, Niu CC, Yang WE, Chen WJ, Shih CH. Spontaneous bilateral patellar tendon rupture in primary hyperpara­ thyroidism. Orthopedics 1999, 22: 1177-9.

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REFERENCES

9. Modrego FJ, Molina J. Bilateral rupture of the quadriceps tendon. Rev Fac Cien Med Univ Nac Cordoba 2004, 61: 37-9.

1. Stefenelli T, Mayr H, Bergler-Klein J, et al. Primary hyperpara­ thyroidism: incidence of cardiac abnormalities and partial reversibility after successful parathyroidectomy. Am J Med 1993, 95: 197-202.

K e c i r t i d E E , L 7 B 0 A T © 20 N RI

10. De Yoe BE, Ng A, Miller B, Rockett MS. Peroneus brevis tendon rupture with tophaceous gout infiltration. J Foot Ankle Surg 1999, 38: 359-62.

2. Symons C, Fortune F, Greenbaum RA, Dandona P, et al. Cardiac hypertrophy, hypertrophic cardiomyopathy, and hyperparathyroidism--an association. Br Heart J 1985, 54: 539-42.

11. Preston ET. Avulsion of both quadriceps tendons in hyperparathyroidism. JAMA 1972, 221: 406-7. 12. Meneghello A, Bertoli M. Tendon disease and adjacent bone erosion in dialysis patients. Br J Radiol 1983, 56: 915-20.

3. Bilezikian JP, Silverberg SJ, Shane E, Parisien M, Dempster DW. Characterization and evaluation of asymptomatic primary hyperparathyroidism. J Bone Miner Res 1991, 6 (Suppl 2): S85-9 discussion: S121-4.

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13. Clark RF, Popky LM, Evans TC. Spontaneous four-extremity extensor tendon rupture in a renal dialysis patient. Ann Emerg Med 1989, 18: 783-4.

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