Br. J. Surg. Vol. 63 (1976) 927-928

Hyperparathyroidism associated with a parathyroid cyst: an unusual presentation E. P . S I M K I N * SUMMARY

in a case of hyperparathyroidism associated with a large parathyroid cyst a causal association was demonstrated by the presence of enormous quantities of parathornione in the cyst fluid. Assay of hormone levels in the cyst fluid in future cases may be helpful in elucidating the aetiology of this rare condition.

Case report A 52-year-old dock foreman was admitted for operation on his severe bilateral varicose veins in September 1974. He was otherwise perfectly fit and symptomless and admitted to no previous illnesses or operations other than a history of penicillin hypersensitivity noticed when given this antibiotic by his general practitioner for an attack of thrombophlebitis. Routine preoperative examination showed that the trachea was deviated to the right, and careful examination of the neck then showed a little enlargement of the left lobe of the thyroid which was perhaps slightly nodular. When the patient was placed in the supine position with the neck fully extended a mass appeared to rise out of the superior mediastinum on the left, particularly on swallowing. The swelling felt soft and circumscribed, but at the time the particular significance of the consistency was not realized. The patient seemed to be euthyroid. Examination of the vocal cords by indirect laryngoscopy showed nothing abnormal. The blood pressure was lSO/lOO mm Hg. In view of the clinical findings, treatment for the varicose veins was postponed and further investigations into the neck swelling were carried out. Blood examination showed: haemoglobin 13.3 g/lOO ml, WBC 7.5 x lO’/litre, ESR 12 mm in 1 hour (Westergren), serum creatinine 1.2 mg/lOO ml, plasma urea 34 mg/100 ml, plasma C O , 28 mEq/l, plasma chloride 104 mEq/l, plasma potassium 4.4 mEq/l, plasma sodium 137 mEq/l. Total serum proteins were 6.6 g/lOO ml, with a serum albumin of 3.8 g/lOO ml and a serum globulin of 2.8 g/lOO ml, total serum bilirubin 0.4mg/ 100 ml, and serum alkaline phosphatase 8 u./litre. Serum triiodothyronine uptake (T3) was 96 per cent and serum thyroxine (T,) 4.6 pg/nil. The thyroglobulin autoprecipitation test was negative. A random serum calcium examination showed a level of 16.4 mg/100 ml, with a serum phosphate of 1.7 mg/100 ml. Further serial serum calcium estimations showed levels of 15.9, 13.4 and 12.6 mg/100 mi. In a calcium excretion study the 24-hour volume of urine was 2410 ml, with a urinary calcium of 19.4 mg/100 ml, giving an excretion of460 mg/24 h. A cortisone suppression test showed no reduction of serum calcium levels over a 10-day period. A serum parathormone estimation was reported as 2.48 ng/ml. A radiological survey showed no bone change or renal calculi. X-ray of the chest and neck showed deviation of the trachea to the right by what appeared to be an enlarged thyroid, but there was no indication of any retrosternal space-occupying lesion. A radioactive iodine scan showed, however, that not only the trachea but also the whole thyroid gland were displaced towards the right. The right lobe appeared normal while the left lobe was truncated with no activity in the lower half. A selenomethionine scan showed no specific increase in uptake in the inactive portion of the gland, indicating that the lesion was probably nonmalignant. There was no evidence of retrosternal thyroid tissue. As there was no history of excessive intake of calciumcontaining foods, vitamin D or alkalis and no evidence of

sarcoidosis or bone malignancy, a diagnosis of parathyroid adenoma was made. Exploration of the neck was carried out on 21 November 1974 through a standard collar incision with division of the strap muscles. It was immediately seen that there was a large, soft, thin-walled cyst below the inferior pole of the left lobe of the thyroid, rising upwards from the anterior superior mediastinum. The diameter was very roughly 10 cm. The cyst was very adherent anteriorly and medially. To facilitate its mobilization 50 ml of fluid were aspirated and at least another 100 ml of fluid were removed by the sucker. The cyst was then mobilized. This procedure was particularly difficult as the left recurrent laryngeal nerve was adherent to the medial wall of the cyst. Thorough examination of the neck following full mobilization of both thyroid lobes showed no evidence of any tumour or parathyroid tissue and the wound was therefore closed with suction drainage. The histological report confirmed the frozen section report at the time of operation and was as follows: ‘The specimen was a collapsed thin-walled cyst with two small firm white nodules in its wall. Paraffin section showed the two nodules to consist of parathyroid tissue. Chief cells and clear cells were present; they were arranged in groups, small columns and acini. Some of the acini were distended by thin colloid. The cyst wall consisted of fibrous tissue in which isolated chief and clear parathyroid cells and atrophic acini were present. The appearances suggested that the larger cyst arose from cystic degeneration of clear cell acini.’ Subsequent assay of the cyst fluid showed a parathormone level of 1100 ng/ml, i.e. approximately 1200 times the upper limit of normal for parathyroid hormone in the blood. During the first few days after the operation the wound appeared perfectly satisfactory and all the skin clips were removed by the third day. However, signs of sepsis developed and the wound broke down in its central portion. Definite signs of an oesophageal fistula appeared on the seventh day. In view of this, intravenous feeding was commenced and all oral intake was stopped. On this regime the fistula rapidly healed and a barium swallow showed nothing abnormal. Normal feeding by mouth was then recommenced without ill-effects and the patient was discharged shortly afterwards. Postoperatively, the serum calcium levels rapidly fell, reaching 9.6 mg/100 ml at 24 hours, 8.6 mg/100 ml at 48 hours and 7.9 mg/lOO ml at 72 hours. A few days later the level rose to 8.4 mg/100 ml, fell transiently to 7.6 mg/100 ml and finally rose to 9.0mg/lOOml. It has remained slightly above this figure since then; this is the lower limit of normal for this hospital laboratory. At review 6 weeks later the serum calcium level was 9.3 mg/ 100 ml. At this time the patient felt perfectly well butcomplained of some weakness of the voice and a ‘catch’ on swallowing. Laryngoscopy and oesophagoscopy showed nothing abnormal and shortly afterwards his symptoms settled completely. He was finally admitted for operation on his varicose veins on 4 March 1975, at which time the serum calcium was 9.3 me/ 100 ml and the serum parathormone level was 0.08 ng/ml.

Discussion Normal parathyroid glands and particularly simple adenomas sometimes contain microscopic cysts, but sizeable cysts are very unusual. Kirwan (1974)

* Sefton General

Hospital, Liverpool.

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E. P. Simkin reported that by 1967 only 58 cases had been recorded; parathormone content. The fact that the level of these included 21 cases collected by the Mayo Clinic. parathormone was extremely high both in the cyst The most favoured opinion is that the cysts arise by fluid and in the blood indicates that the nodules of degeneration in a parathyroid adenoma, but this can parathyroid tissue in the wall had been secreting into the cyst and that the hormone had then been released only be a matter of speculation. Associated evidence of hyperparathyroidism is into the circulation. It is of particular interest to note extremely rare. One of the 4 cases described by that apart from the biochemical changes the patient Kirwan was shown to have hyperparathyroidism had no overt manifestations of hyperparathyroidism. preoperatively, and he cited 4 other cases of a cyst Rogers et al. (1969) and Howell (1972) described 3 with hyperparathyroidism (Shields and Staley, 1961 ; cases presenting with hyperparathyroidism, all the Haid et al., 1967; Rogers et al., 1969). These 5 cases other cases described being diagnosed postoperatively together with the case described here and that when the pathology reports were available. It can be described by Howell (1972) make a total of 7 cases in said with certainty that parathyroid cyst associated the world literature. The rarity is reflected in the fact with hyperparathyroidism is rarer than parathyroid that Pyrah et al. (1966), in their exhaustive review of cyst with no abnormal hormonal effect. The case primary hyperparathyroidism, made no mention of described here is a true example of serendipity in that parathyroid cysts in association with hyperpara- a raised serum calcium was found by chance examination. thyroidism. There has been only one case report of a parathyroid cyst which had been identified preoperatively. Acknowledgements The identification was made by aspiration of the cyst I would like to thank Dr J. H. Goldsmith, Consultant and cytological examination of the aspirated fluid Nephrologist, Sefton General Hospital, for his (Crile and Perryman, 1953). All the other cases have assistance in investigating this case and Dr J. L. H. presented as a neck swelling which had been presumed O’Riordan, Department of Medicine, The Middlesex initially to be a solid parathyroid tumour. On simple Hospital, for carrying out the hormone level assays. clinical examination it is very difficult to distinguish between solid and cystic lesions. However, if in a case References with raised serum calcium, examination of the neck CRILE G. J . R . and PERRYMAN R. c. (1953) Parathyroid cysts; report of five cases. Surgery 34, 151-154. shows a palpable mass which is far too big for an adenoma the diagnosis of a cyst should be considered HAID S. P., METHOD H. L. and BEAL J. M. (1967) Paraand an attempt made to aspirate fluid from it for thyroid cysts. Report of 2 cases and a review of hormone assay. the literature. Arch. Surg. 94, 421-426. The outstanding features of the cyst in the present HOWELL A. (1 972) Occult hyperparathyroidism precase were its large size, its adherence to surrounding senting as a parathyroid cyst. Proc. Soc. Med. tissues, including the left recurrent laryngeal nerve, 65, 881-882. and the difficulty encountered in dissecting it from the KIRWAN w . 0.(1974) Parathyroid cyst. Br. J. Surg. 61, surrounding tissues. All previous reports have stated 365-367. that these cysts are seldom large and do not prove PYRAH L. N., HODGKINSON and ANDERSON c. K. (1966) troublesome to remove. Reviewing the radioactive Primary hyperparathyroidism. Br. J. Surg. 53, iodine scan, the diagnosis of cyst should have been 245-3 16. suspected as in retrospect the thyroid gland was ROGERS L. A . , FETTERS B. F. and PEETE w. P. J. (1969) markedly displaced with much deformity of the lower Parathyroid cyst and cystic degeneration of pole of the lateral lobe, suggesting a large lesion parathyroid adenoma. Arch. Pathol. 88, 476extrinsic to the thyroid gland. 479. There is no previously recorded case in the world SHIELDS T. w. and STALEY c. J. (1961) Functioning literature in which the cyst fluid has been assayed for parathyroid cyuts. Arch. Surg. 175, 937-942.

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Hyperparathyroidism associated with a parathyroid cyst: an unusual presentation.

In a case of hyperparathyroidism associated with a large parathyroid cyst a causal association was demonstrated by the presence of enormous quantities...
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