CASE REPORT Dennis H. Kraus, MD, Section Editor
PARATHYROID ADENOMA AUTOINFARCTION: A REPORT OF A CASE Satish Govindaraj, MD,1 Jared Wasserman,2 Rod Rezaee, MD,1 Adam Pearl, MD,1 Donald A. Bergman, MD,3 Beverly Y. Wang, MD,4 Mark L. Urken, MD1 1
Department of Otolaryngology, Campus Box 1189, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York 10029. E-mail:
[email protected] 2 Mount Sinai School of Medicine, New York 3 Department of Endocrinology, Mount Sinai Medical Center, New York 4 Department of Pathology, Mount Sinai Medical Center, New York Accepted 7 October 2002 Published online 23 June 2003 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/hed.10244 Abstract: Background. Parathyroid adenoma autoinfarction, although uncommon, is an entity that has been previously reported in the literature; however, the influence of intraoperative parathyroid hormone (PTH) monitoring on therapeutic management has not been reported. Methods. We present a case of parathyroid autoinfarction that is unique in that it applies a new technology to parathyroid surgery: intraoperative PTH monitoring. Results. Intraoperative PTH monitoring aided in the successful surgical management of this patient. Conclusions. Intraoperative PTH monitoring can serve as a therapeutic adjunct in the surgical management of parathyroid adenoma autoinfarction. © 2003 Wiley Periodicals, Inc. Head Neck 25: 695–699, 2003 Keywords: hyperparathyroidism; autoinfarction; adenoma; hypercalcemia; PTH
Parathyroid
adenoma autoinfarction, although uncommon, is an entity that has been previously
Correspondence to: M. L. Urken © 2003 Wiley Periodicals, Inc.
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reported in the literature.1–14 The mechanism of action has yet to be determined, and patient presentation varies from case to case. Patients may have complete resolution of their signs and symptoms without operative resection, and others have shown delayed recurrence of parathyroid hyperfunction requiring subsequent resection. Patients tend to have neck discomfort and a palpable neck mass with variable calcium levels ranging from low, to normal, to high. We present a case of parathyroid autoinfarction that is unique in that it applies a new technology to parathyroid surgery: intraoperative parathyroid hormone (PTH) monitoring. MATERIALS AND METHODS
This patient is a 46-year-old woman with a 11⁄2 year history of hypercalcemia. She showed signs of end organ involvement from the disease, including nephrolithiasis and severe osteoporosis. She denied any history of peptic ulcer disease, pancreatitis, or symptoms of nausea, vomiting, or
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weakness. She had elevated calcium levels to 13 mg/dL 2 weeks before admission for which a trial of calcitonin was administered. She subsequently had symptoms of right-sided headaches and severe throat pain, which eventually resolved spontaneously. At the time when she was symptomatic, her PTH level was measured at 533 pg/mL, and physical examination was significant for a 5-cm mass in the right thyroid bed that caused compressive symptoms. Before operative intervention, the patient’s calcium levels had returned to normal, with persistence of compressive symptoms from the right paratracheal mass. Before surgical intervention, the patient underwent diagnostic imaging consisting of a technetium-99m sestamibi scan and CT scan of the neck with intravenous contrast. No definite localization of a parathyroid adenoma was noted on the study; however, an area of discongruent activity on 99mTC-sestamibi images was noted just medial to the midportion of the right thyroid gland. A CT scan was then performed, which revealed a 3-cm cystic lesion at the posterior inferior aspect of the right thyroid gland correlating with the location on the sestamibi scan. The mass originated at the inferior aspect of the thyroid gland extending inferiorly a distance of 3 cm to the suprasternal notch (Figure 1).
Whether the lesion was of thyroid or parathyroid origin was indeterminate. RESULTS
The patient was taken to the operating room for neck exploration and planned parathyroidectomy. Intraoperatively, the mass was easily identified and noted to be distinct from the right thyroid lobe with a significant inflammatory reaction on its surface. The mass extended laterally deep to the carotid artery and inferiorly below the level of the innominate. Despite its anatomic relationships and inflammatory reaction, the mass was delivered intact. Intraoperative PTH monitoring revealed a baseline PTH level of 149 pg/mL, which failed to demonstrate any drop after excision (Table 1) (QuiCk-IntraOperative Intact PTH Kit; Nichols Institute Diagnostics, San Juan Capistrano, CA). For this reason, an exploration of the left neck was conducted, which revealed no parathyroid enlargement. Based on the higher preoperative PTH level of 533 pg/mL and a normalized calcium level in the immediate preoperative period, it was thought that the adenoma had undergone autoinfarction and thus failed to produce the usual threshold fall in the PTH assay as a result. Frozen section was consistent with an enlarged (5.2 g) parathyroid gland with areas of
FIGURE 1. Mass extends below the level of the thyroid gland along right lateral tracheal wall. There is no intraluminal extension of the mass into the trachea. The black arrows outline the borders of the mass.
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Table 1. Intraoperative parathyroid hormone levels. Time
PTH concentration (pg/mL)
Baseline After isolation Time zero Five min after excision Ten min after excision Twenty min after excision Forty-five min after excision
149 163 155 168 180 179 148
necrosis and hemorrhage. The specimen grossly measured 2 × 1.2 × 2 cm. Final pathologic findings were consistent with an infarcted parathyroid gland with neovascularizing granulation tissue (Figure 2). The patient underwent an uncomplicated postoperative course with stable ionized calcium levels and was subsequently discharged home. She has been followed for a period of 12 months and has remained eucalcemic. DISCUSSION
The search for hyperfunctioning parathyroid tissue requires knowledge of the embryology and anatomy of these glands to perform a successful systematic search. The parathyroid glands are endodermal derivatives. The inferior parathyroid gland is derived from the third pharyngeal pouch,
and the superior parathyroid gland takes its origin from the fourth. The superior parathyroid glands are located at the cricothyroid joint, where the recurrent laryngeal nerve enters the larynx, whereas the inferior parathyroid glands are located at the inferior pole of the thyroid consistently below the level of the recurrent laryngeal nerve and inferior thyroid artery crossing.14 Although normally at the inferior pole of the thyroid gland, the inferior parathyroid glands may be located anywhere along their path of descent with the thymus, including within the superior mediastinum. In most cases, patients have four parathyroid glands (greater than 80%), but individuals may demonstrate either a supernumerary state (13%) or possibly fewer than four glands (3%).14 In addition, a failure to locate parathyroid tissue may be secondary to an intrathyroidal location (1.3%).14 Parathyroid glands are responsible for the creation of parathyroid hormone (PTH), a straight chain peptide. PTH acts directly on bone and kidney and indirectly on the gastrointestinal tract by means of vitamin D to increase serum calcium levels and decrease serum phosphate levels. An appreciation of these effects is critical to the care of these patients, because a hyperfunctional state
FIGURE 2. Photomicrograph of autoinfarcted parathyroid adenoma. The figure demonstrates relatively preserved parathyroid gland (P) with adjacent acellular debris from gland autoinfarction (I). Note the outer layer showing organizing granulation tissue formation (G). [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]
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of this system can lead to significant secondary end organ dysfunction. This includes peptic ulcer disease, acute pancreatitis, ectopic calcification, renal calculi, high output renal insufficiency, psychosis, and bony abnormalities such as osteitis fibrosa cystica and more commonly osteopenia. Primary hyperparathyroidism is the most common cause of nonhospitalized hypercalcemia. Surgical management in the medically stable patient is the standard of treatment for primary hyperparathyroidism in those patients who are symptomatic or possess a serum calcium level greater than 1 mg/dL above the upper limit of normal.14 Adenoma autoinfarction has resulted in spontaneous resolution of primary hyperparathyroidism.1–13 The earliest description of this entity was by Norris in 1946.1 Since this initial description, several cases have been reported, most recently in 1998 by Kovacs and Gay12 and Otsuka et al.13 The clinical presentation, laboratory values, and physical examination findings of our patient were consistent with previously described cases in the literature. Natsui et al11 divided the clinical presentation of parathyroid adenoma into three potential stages. The first is a sudden release of PTH from the infarcted, necrosed gland that causes an acute transient hyperparathyroid state. The cases in the literature have described this phase as lasting up to 2 weeks. This is followed by the potential for acute hypocalcemia, especially in those patients with previous bone involvement. This is likely due to remaining parathyroid gland suppression and the hungry bone syndrome associated with hyperparathyroidism. The third stage is eventual return to normocalcemia. This phase can be transient, because PTH levels may again surge secondary to incomplete gland infarction as has also been reported.11 This supports surgical removal of the infarcted gland. The pathophysiology of this entity remains unknown. In a review of the literature by Kovacs and Gay, seven of eight clinical cases had adenomas larger than 2 cm in diameter at the time of pathologic analysis of the specimen. Because this measurement is taken after infarction, the presence of a large, hyperfunctioning gland that outgrows its blood supply is a plausible explanation, although difficult to reconcile because of the slow, progressive nature of this condition. In addition, the severe pain experienced by our patient preoperatively may have been secondary to parathyroid ischemia. A unique feature of our case was the use of
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intraoperative PTH monitoring. Listed in Table 1 are the intraoperative PTH levels for our patient. As can be seen, the postisolation and postexcision levels are essentially unchanged, which indicates that the previously hyperfunctioning adenoma (preoperative level of 533 pg/dL) had undergone autoinfarction with subsequent stabilization of PTH levels. There have been reports of autoinfarcted adenomas that have been followed by serial ultrasonography rather than surgical resection.10,12 Although this is an acceptable means of management, reports of postinfarction progressive elevation in PTH levels11 are a strong argument for definitive management with surgical resection. In addition, most reports cited in the literature were managed with resection of the infarcted adenoma rather than expectant management.1–9,11,13,14 Our patient had persistent local symptoms that resolved after definitive surgical management. Intraoperative PTH monitoring has been shown to be a valuable tool for guiding intraoperative surgical decision making in the detection of residual adenoma function, which would be indicated by a further drop in PTH levels after excision. In a normally functioning adenoma, a 50% drop is expected 20 minutes after excision.15 In our case, the failure to see a drop in postexcision intact PTH and the maintenance of a normal postoperative calcium level confirms the fact that the enlarged parathyroid gland had autoinfarcted and at the time of surgery was no longer functional. Intraoperative PTH monitoring can serve as a therapeutic adjunct in the surgical management of parathyroid adenoma autoinfarction and permits the detection of residual adenoma function, thus decreasing the risk of recurrent primary hyperparathyroidism. In summary, we have highlighted and reviewed a previously reported clinical entity, parathyroid adenoma autoinfarction, with an emphasis on the role of intraoperative PTH monitoring in the management of these patients.
REFERENCES 1. Norris EH. Primary hyperparathyroidism. Arch Pathol 1946;42:261–273. 2. Howard JE, Follis RH Jr, Yendt ER, Connor TB. Hyperparathyroidism. Case report illustrating spontaneous remission due to necrosis of adenoma, and a study of the incidence of necroses in parathyroid adenomas. J Clin Endocrinol Metab 1953;13:997–1008. 3. Dowlatabadi H. Acute fatal parathyroid poisoning associated with necrosis of the parathyroid adenoma prior to death. J Clin Endocrinol Metab 1959;19:1481–1485.
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4. Johnston CC Jr, Schnute RB. A case of primary hyperparathyroidism with spontaneous remission after infarction of the adenoma with development of hypocalcemic tetany. J Clin Endocrinol Metab 1961;21:196–200. 5. Connor TB, Clark JW, Martin LG, Lovice H. Intermittent hyperparathyroidism. Trans Am Clin Climatol Assoc 1965;77:80–95. 6. Northcutt RC, Levinson JD, Earnest JB. Hypocalcemia resulting from infarction of a parathyroid adenoma. Ann Intern Med 1969;70:353–356. 7. McLatchie GR, Morris EW, Forrester A, Fogelman I. Autoparathyroidectomy: a case report. Br J Surg 1979;66: 552–553. 8. Hotes LS, Barzilay J, Cloud LP, Rolla AR. Spontaneous hematoma of a parathyroid adenoma. Am J Med Sci 1989; 297:331–333. 9. Mir R, Gerold T, Khan S, Weitz J. Spontaneous infarction of parathyroid adenoma: a case report and literature review. Head Neck 1993;15:566–568. 10. Onoda N, Miyakawa M, Sato K, Demura H, Uchida E. Spontaneous remission of parathyroid adenoma followed with ultrasonographic examinations. J Clin Ultrasound 1994;22:134–136.
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11. Natsui K, Tanaka K, Suda M, Yasoda A, Yonemitsu S, Nakao K. Spontaneous remission of primary hyperparathyroidism due to hemorrhagic infarction in the parathyroid adenoma. Intern Med 1996;35:646–649. 12. Kovacs KA, Gay JD. Remission of primary hyperparathyroidism due to spontaneous infarction of a parathyroid adenoma: case report and review of the literature. Medicine 1998;77:398–402. 13. Otsuka F, Ogura T, Sato T, et al. Hypocalcemia due to spontaneous infarction of parathyroid adenoma and osteitis with primary hyperparathyroidism. Endocrinol J 1998;45: 617–623. 14. Summers GW. Surgical management of parathyroid disorders. In: Cummings CW, Fredrickson JM, Harker LA, Krause CJ, Schuller DE, Richardson MA, editors. Otolaryngology Head and Neck Surgery, ed 3. St. Louis: Mosby– Year Book; 1998. p 2519–2529. 15. Irvin GL, Molinari AS, Figueroa C, Carneiro DM. Improved success rate in reoperative parathyroidectomy with intraoperative PTH assay. Ann Surg 1999;229: 874–879.
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