Parathyroid carcinoma: diagnosis and management

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EJSO 2001; 27: 321–324 doi:10.1053/ejso.2001.1043, available online at http://www.idealibrary.com on

Parathyroid carcinoma: diagnosis and management J. J. Sheehan∗, A. D. Hill∗, M. F. Walsh† T. B. Crotty†, E. W. McDermott∗ and N. J. O’Higgins∗ ∗Department of Surgery, †Department of Pathology, St. Vincent’s University Hospital, Elm Park, Dublin 4, Ireland

Parathyroid carcinoma is a rare and difficult diagnosis to make based on the histological features alone. We review five cases of parathyroid carcinoma in the past 30 years and the clinical and biochemical features that facilitate the making of the diagnosis. A favourable outcome can be expected with adequate surgical treatment.  2001 Harcourt Publishers Ltd Key words: parathyroid; carcinoma; primary hyperparathyroidism; sestamibi.

INTRODUCTION Parathyroid carcinoma is a rare neoplasm, representing between 0.5 and 5% of all cases of primary hyperparathyroidism. Diagnosis of this disease often proves difficult for both clinicians and pathologists as its features overlap those of benign parathyroid neoplasms, making a preoperative and postoperative diagnosis of malignancy difficult. The purpose of this report is to review our experience with five cases of parathyroid carcinoma.

METHODS There were 251 patients who underwent cervical exploration for primary hyperparathyroidism between 1970 and 1999. Of these, five patients (2%) were diagnosed with parathyroid carcinoma. The medical records of all cases of parathyroid carcinoma were reviewed. The following particulars were noted: age, gender, clinical features, serum calcium and parathyroid hormone concentration before and after surgical management, operative procedures and findings, pathology and survival (Table 1).

RESULTS Five patients were identified (3 male, 2 female), with a mean age of 58 years (range 41–69 years). All were

Correspondence to: Prof. Niall O’Higgins, St. Vincent’s University Hospital, Elm Park, Dublin 4, Ireland. Tel: 353 1 269 4533; Fax: 353 1 269 6018; E-mail: [email protected] 0748–7983/01/030321+04 $35.00/0

hypercalcaemic at diagnosis (mean pre-op serum calcium concentration, 3.19 mmol/l (range 2.87–3.4 mmol/l)). This compared to a mean preoperative serum calcium of 2.93 for those patients with parathyroid adenoma. Clinical features at presentation were weakness/fatigue (n=3), bone pain (n=2), nephrocalcinosis (n=2), peptic ulcer (n=1), palpable neck mass (n=1), renal stone (n= 1), and depression (n=1). Preoperative localization was utilized in one patient using Tc/Sestamibi scintigraphy localizing the lesion behind the mid-portion of the left lobe of the thyroid at the junction with the isthmus. All carcinomas were located in one of the inferior parathyroid glands. The average diameter of the tumours was 2.8 cm (range, 1.5–5 cm). The colour of the gland was noted to be grey in three of the cases. Three patients underwent simple excision of tumour with no difficulty noted in dissecting the gland free. Another underwent en bloc excision because of adherence but not invasion of the thyroid and trachea. The remaining case underwent excision of tumour along with the recurrent laryngeal nerve and ipsilateral thyroidectomy because of invasion of adjacent muscle and thyroid and adherence to the carotid sheath and recurrent laryngeal nerve. This patient received post-operative radiotherapy to the site to prevent future recurrence. Marking of the gland bed with clips was not deemed necessary. Pathology findings are shown in Table 2. The duration of follow up ranged from 1 to 18 years (mean, 7.8 years). No patient had persistent hyperparathyroidism. One patient was lost to follow up after seven years. Another patient developed a local recurrence after 11 years. This was detected by the presence of an elevated serum calcium and an area of increased uptake on a Tc-99m sestamibi and pertechnetate  2001 Harcourt Publishers Ltd

56

41 64

60

69

1

2 3

4

5

M

F

M F

M

Sex

1998

1997

1981 1988

1979

Year of operation

3.26

2.87

3.3 3.07

3.4

Pre-op calcium∗

154

130

n/a 152

n/a

Pre-op PTH∗∗

Invasion of muscle and thyroid No invasion

No invasion No invasion

No invasion

Operative findings

n/a

n/a

1240 930

9690

Weight (mg)

3×2×1

3×1×0.5

1.5×1 1.5×1×1

5×2.5×2

Size (cm)

Excision of tumour and ipsilateral thyroidectomy Excision of tumour

Excision of tumour Excision of tumour

Excision of tumour

Operation

∗Reference range=2.2 to 2.6 mmol/l; ∗∗Reference range=2 to 52 ng/l; NED=No evidence of disease; n/a=Not available.

Age

No.

Table 1 Clinical details

1

2

18 11

7

Duration of follow up (years)

NED 1999

Lost to follow up – 1986 NED 1999 Local recurrence 1999 NED 1999

Outcome

322 EDUCATIONAL SECTION

EDUCATIONAL SECTION

323

Table 2 Pathological findings 1

2

3a∗

3b∗∗

4

5

Nuclear atypia Mitoses

Marked No

Mild No

Mild No

Mild No

Fibrous trabeculae

No

Yes

Thick capsule Uniform cell

Yes No

Yes (Prominent) Yes Yes

Yes No

Moderate Yes (Occasional) Yes (Prominent) Yes No

Capsular invasion

Yes

Yes

Yes Yes (Some) Yes

Mild Yes (Rare) Yes (Prominent) Yes Yes

Yes

Yes

Vascular invasion

Yes

Yes

Yes

Yes (into fat) —

Yes

Yes

Yes

∗Original tumour 1988; ∗∗Tumour recurrence 1999.

scan. Metastases did not develop in any of the five patients.

DISCUSSION The 2% incidence of malignant hyperparathyoidism falls within the range of 0.5% to 5% reported by other investigators. Similar to other studies our patient group showed that patients with parathyroid carcinoma have higher serum calcium levels at presentation than those with benign hyperparathyroidism. Only 10% of parathyoid adenomas are palpable whereas parathyoid carcinomas palpable on clinical examination range from 32% to 69%.1 In our series only one patient out of five (20%) presented with a palpable mass. The incidence of neurologic symptoms (fatigue and depression), renal stones and bone disease in our series was similar to those described by others.1 All five parathyroid tumours were in the inferior parathyroid glands. Although this finding has been reported elsewhere,2 its significance remains unclear. Malignancy may be suspected before surgery with a significantly elevated serum calcium, high plasma parathyroid hormone, evidence of generalized bone disease or in a hypercalcaemic patient with a palpable neck mass. Any parathyroid gland with a grey appearance, firm texture, or adherence to surrounding tissue must be treated as carcinoma. Frozen section diagnosis is typically difficult, and therefore malignancy cannot be ruled out with certainty. In our series the suspicion of malignancy was raised in three cases perioperatively. Clinical suspicion of carcinoma guides the extent of the operation. Surgical removal of the tumour is at present the only effective therapy for parathyroid carcinoma.1 The diagnosis of parathyroid carcinoma is often made after a local recurrence or when a remote metastasis has become apparent.6 Fujimoto et al.3 state that although the prognosis of parathyroid carcinoma greatly depends on the biological

malignancy of the tumour in individual cases, their ongoing data confirms the importance of thorough identification and en bloc removal of the tumour at the initial time of the operation and neck dissection is necessary when there is evidence of lymph node metastasis. Surgical excision is often curative when the malignant nature of the tumour is recognized at the initial operation and adequate resection is performed. Surgical management can be graded according to the extent of the tumour and may involve simple excision, en bloc resection, including resection of local structures such as the ipsilateral thyroid, thymus, strap muscles and recurrent laryngeal nerve. It has been suggested that in order to prevent local recurrences which are rarely curable,4 integrity of the capsule of the parathyroid gland is maintained by gentle dissection, ipsilateral thyroid lobectomy, and en bloc dissection of the tracheoesophageal groove. In our experience, ipsilateral thyroidectomy was only performed when there was invasion of the thyroid gland. If there is adherence to the recurrent laryngeal nerve, the nerve should be sacrificed.5 Radical neck dissection is reserved for those with extensive local invasion, multiple enlarged cervical nodes, or patients who have undergone reoperation in whom scarring prevents accurate delineation of the extent of the tumour.5 Several articles have demonstrated no improvement in survival with prophylactic radical neck dissections.6 The histologic characteristics that are used in determining malignancy in other organs do not always apply to tumours of the parathyroid gland.7 Parathyroid carcinoma is difficult to diagnose microscopically because of the similarities between an adenoma and a carcinoma. Mitosis and giant cells occur in adenomas and are of little value as specific criteria of malignancy. Cellular pleomorphism per se is not a reliable indicator of malignancy in endocrine neoplasms.8 An unequivocal diagnosis of carcinoma can only be made if there is

324 extension through the capsule, invasion of lymphatic spaces and into contiguous structures or lymph nodes or if there are distant metastases. It is important therefore to establish a set of histological criteria to diagnose carcinoma. Schantz and Castleman suggested that the presence of mitoses within parenchymal cells is the single most important criterion.9 The diagnosis of parathyroid carcinoma by histology alone is difficult, and may lead to overdiagnosis.8 The presence of clinical and biochemical features of parathyroid malignancy should be considered in making the diagnosis of parathyroid carcinoma. Fujimoto et al., demonstrated a 4.2% incidence of malignant hyperparathyroidism. All seven cases reported showed unequivocal histological evidence of parathyroid carcinoma. These included vascular and capsular invasion, formation of dense fibrous capsule and trabeculae, solid and trabecular cell growth pattern, rather monotonous tumour cells, and a large nucleus with predominant nucleoli and mitosis.3 In our series all five cases had some nuclear atypia, thickened capsule, capsular invasion and vascular invasion. The natural history of parathyroid carcinoma is typically characterized by slow growth, amenable to repeated resections of local recurrences, but seldom for cure.10 When death is attributable to the disease, it is usually secondary to hypercalcaemia and its effects (renal failure, pancreatitis, or cardiac arrhythmia) rather than being a result of direct extension of the tumour and its satellites.5 Therefore biochemical normalization of the disease should be the principal aim of treatment.1 Even

EDUCATIONAL SECTION among the 30% or so of patients in whom the tumours metastasize, fewer than 50% will die from the disease within 5 years.9 Patients who have recurrence of hyperparathyroidism after surgical treatment should be suspected of having recurrent or persistent parathyroid carcinoma.7 Parathyroid carcinoma is associated with a satisfactory long term prognosis as shown by our five patients of whom four had only a simple resection.

REFERENCES 1. Favia G, Lumachi F, Polistina F, et al. Parathyroid carcinoma: Sixteen new cases and suggestions for correct management. World J Surg 1998; 22: 1225–30. 2. Al-sobhi S, Ashari L, Ingemansson S. Detection of metastatic parathyroid carcinoma with Tc-99m sestamibi imaging. Clin Nucl Med 1999; 24: 21–2. 3. Fujimoto Y, Obara T, Ito Y, et al. Surgical treatment of ten cases of parathyroid carcinoma: Importance of initial en bloc tumour resection. World J Surg 1984; 8: 392–400. 4. Shane E, Bilezikian J. Parathyroid carcinoma: A review of sixty-two patients. Endocrine Rev 1982; 3: 218–26. 5. Cohn K, Silverman M, Corrado J, et al. Parathyroid carcinoma: The Lahey Clinic experience. Surgery 1985; 98: 1095–9. 6. Jarman W, Myers R, Marshall R. Carcinoma of the parathyroid. Arch Surg 1978; 113: 123–5. 7. Van Heerden J, Weilnad L, ReMine W, et al. Cancer of the parathyroid glands. Arch Surg 1979; 114: 475–80. 8. McKeown P, McGarity W, Sewell C. Carcinoma of the parathyroid gland: is it overdiagnosed? Am J Surg 1984; 147: 292–8. 9. Schantz A, Castleman B. Parathyroid carcinoma. A study of 70 cases. Cancer 1973; 31: 600–5. 10. Flye M, Brennan M. Surgical resection of metastatic parathyroid carcinoma. Ann Surgery 1981; 193: 425–35.

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