Parathyroid carcinoma: a 22-year experience

[An historical case of malignant hyperparathyroidism with unusual metastatic sites]

We report a historical case of hyperparathyroidism in a young patient hospitalized for an array of osteolytic foci and incomplete fracture associated with a swollen neck, revealing a very special form of a metastatic parathyroid carcinoma with unusual multiple locations and exceptional medullary flooding. Carcinoma of the parathyroid gland produces a malignant hypersecreting tumor particularly difficult to diagnose. Treatment of this rare tumor is primarily surgical. The preoperative syndrome is unusually severe primary hyperparathyroidism. Intraoperatively, the size of the tumor and its local extension to surrounding tissue are highly suggestive. Confirmation requires pathological analysis of the operative specimens and can be further supported by the clinical course of local recurrence or metastasic spread. Specific immunohistochemical techniques have recently been shown to be contributive. The diagnosis is strengthened in the presence of associated Schantz and Castelman criteria. Foci of local extension can be identified preoperatively with ultrasound, (99m)Tc-sestamibi scintigraphy and MRI of the neck and mediastinum. The prognosis depends mainly on the possibility of achieving complete resection at the initial surgery. In some cases, very aggressive complementary postoperative radiotherapy is likely to improve locoregional control of the tumor. Chemotherapy alone or in combination with radiation has not demonstrated its effectiveness. The disease course and control can be monitored by regular assay of serum calcium and the parathormone.

Value of intraoperative parathyroid hormone monitoring

BACKGROUND

Routine use of intraoperative parathyroid hormone (IOPTH) has been challenged in both unilateral/limited (LE) and bilateral exploration (BE). To investigate this, we assessed the usefulness of IOPTH in surgical management of primary hyperparathyroidism and parathyroid carcinoma (PC).

METHODS

Between 1998 and 2006, 1133 patients were explored for hyperparathyroidism: 185 LE, 743 BE with IOPTH, 95 BE without IOPTH, 110 reoperations, and 4 PCs. IOPTH patterns were correlated with parathyroid pathology (single adenoma [SA] or multigland disease [MGD]) and operative success.

RESULTS

In LE, IOPTH returned to normal in 78% of patients; all patients had SA, and 99% were cured at a mean +/- SEM of 1.2 +/- .24 years; 22% of LE patients (n = 41) whose IOPTH did not return to normal were converted to BE, and all had MGD. BE with and without IOPTH was equally successful 97% and 98% (P = NS) of the time, respectively. In BE in which IOPTH did not return to normal, 9% of patients remained hypercalcemic; tumor distribution mirrored other BE patients (75% SA, 25% MGD). In reoperations, a normal final IOPTH correlated with cure in 99%; otherwise, 59% had persistent disease. Differential bilateral internal jugular vein IOPTH sampling lateralized disease in 77% of reoperations.

CONCLUSIONS

IOPTH is an important adjunct for successful LE by identifying the presence of MGD and avoiding operative failure. IOPTH adds little to BE; however, final IOPTH values may predict persistent disease in BE, reoperations, and PCs.

Intra-operative parathyroid hormone monitoring in patients with parathyroid cancer

BACKGROUND

Intra-operative parathyroid hormone (PTH) monitoring (IPM) is 97% accurate in predicting postoperative eucalcemia in sporadic primary hyperparathyroidism (SPHPT). However, its usefulness in parathyroid cancer has not been demonstrated. This study reports IPM accuracy during surgical resections for parathyroid cancer.

METHODS

Eight of 556 consecutive patients with SPHPT underwent parathyroidectomy using IPM and had parathyroid cancer. Operative success was defined as eucalcemia > six months and operative failure/persistent cancer as hypercalcemia within six months of parathyroidectomy. The IPM criterion for operative success was defined as a >50% decrease of peripheral PTH levels from the highest either pre-incision or pre-excision values, 10 minutes after resection.

RESULTS

In eight patients, 11 operations were performed. Ten operations (91%) resulted in >50% intra-operative PTH decrease. However, in only seven (70%) of these resections, eucalcemia was achieved for >6 months with five of these seven (71%) procedures being initial en bloc resections. The remaining 3/10 (30%) operations with >50% intra-operative PTH decrease resulted in operative failures. In the last operation, intraoperative parathormone monitoring (IPM) correctly predicted operative failure. IPM sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy in predicting outcome were 100, 40, 70, 100, and 75%, respectively.

CONCLUSIONS

IPM with the criterion of >50% PTH drop from the highest level is less accurate in predicting operative success in parathyroid cancer when compared to SPHPT. A >50% intra-operative PTH level decrease in patients with parathyroid cancer, particularly in reoperative cases, is less predictive of complete resection. The initial recognition of this disease followed by proper resection remains essential in the treatment of parathyroid cancer.

Successful palliation of hypercalcemia secondary to metastatic parathyroid cancer: an unusual indication for hepatic resection

Primary carcinoma of the parathyroid gland is a rare disease. It is often diagnosed after recurrence of hyperparathyroidism following resection for presumed adenomatous disease. Local and distant recurrence is high and aggressive resection is advocated. Patients with parathyroid cancer are frequently plagued by severe hypercalcemia, which is often refractory to medical therapy. Herein we describe the case of a patient with metastatic parathyroid cancer localized to the liver. The patient was treated with a palliative hepatic resection for the management of persistent and refractory hypercalcemia. Intraoperative parathyroid hormone levels were utilized as an adjunct to determine successful metastatectomy. Our case highlights the importance of an aggressive approach to patients with metastatic parathyroid cancer, as well as the utility of intraoperative parathyroid hormone levels to confirm successful extirpation of disease.

Trends in the incidence and treatment of parathyroid cancer in the United States

BACKGROUND

Parathyroid cancer is a rare cause of hyperparathyroidism. The objectives of this study were to determine the patterns of disease, treatment trends, and outcomes among patients with parathyroid cancer by using a population-based data source.

METHODS

Surveillance, Epidemiology, and End Results (SEER) cancer registry data were used to identify patients who were diagnosed with parathyroid cancer from 1988 through 2003. To assess whether the incidence rate, treatment, tumor size, and cancer stage changed over time, the Cochrane-Armitage trend test was used, and Cox proportional-hazards modeling was used to identify the factors associated with an improved overall survival rate.

RESULTS

From 1988 through 2003, 224 patients with parathyroid cancer were reported in the SEER data. Over that 16-year study period, the incidence of parathyroid cancer increased by 60% (1988-1991, 3.58 per 10,000,000 population; 2000-2003, 5.73 per 10,000,000 population). Most patients (96%) underwent surgery (parathyroidectomy, 78.6% of patients; en bloc resection, 12.5% of patients; other, 4.9% of patients). The rate of surgical treatment increased significantly during the study period. The 10-year all-cause mortality rate was 33.2%, and the 10-year cancer-related mortality rate was 12.4%. Patient age (P<.0001), sex (P=.0106), the presence of distant metastases at diagnosis (P=.0004), and the year of diagnosis (P=.0287) were associated significantly with the overall survival rate. Tumor size, lymph node status, and type of surgery were not associated significantly with the overall survival rate.

CONCLUSIONS

Although parathyroid cancer is rare, the incidence increased significantly in the United States from 1988 through 2003. Young age, female gender, recent year of diagnosis, and absence of distant metastases were associated significantly with an improved survival rate.

Myxoid lipoadenoma of parathyroid gland: a case report and literature review

Myxoid lipoadenoma of the parathyroid gland is a rare variant of parathyroid adenoma. We present the case of a 40-year-old man with asymptomatic hypercalcemia who underwent surgical removal of a parathyroid adenoma. Histologically, the tumor consisted of monomorphous round-to-oval chief cells arranged in several architectural patterns including solid sheet-like, trabecular, and follicular. The tumor stroma was prominently myxoid with interspersed mature adipose tissue. Immunohistochemistry confirmed expression of thyroid transcription factor and parathyroid hormone by all tumor cells and a low proliferation rate with a Ki-67 labeling index of at most 5%. Although the lesion exhibited characteristics that have been previously associated with "atypical parathyroid adenoma," such as dense fibrous bands within the tumor and a trabecular growth pattern, there was no further evidence, neither histologically nor clinically, for malignant behavior of the tumor.

Parathyroid carcinoma

PURPOSE OF REVIEW

This article reviews current knowledge on the etiology, diagnosis and treatment of parathyroid carcinoma.

RECENT FINDINGS

Due to its rarity, research on the molecular etiology and treatment of parathyroid carcinoma has been slow. Mutations of the tumor suppressor gene, HRPT2, and resultant loss of expression of its gene product have been found in the majority of parathyroid cancers studied. Recent advances in the field have identified regions on several chromosomes that demonstrate loss of heterozygosity more commonly in parathyroid carcinoma than in benign parathyroid lesions. This has provided clues to the location and identity of additional tumor suppressor genes associated with the development of this cancer.

SUMMARY

Parathyroid carcinoma is an extremely rare cause of primary hyperparathyroidism, accounting for fewer than 1% of cases. The etiology of parathyroid cancer is largely unknown. Associations have been made with several inherited syndromes and with specific genetic lesions. Little is known about the most appropriate management of this disease. En bloc resection at the time of initial surgery appears to provide the best chance of cure. Anecdotal experience with adjuvant chemotherapy has shown a modest and short-lived effect. External beam radiation following surgical resection, however, may increase long-term survival compared with surgery alone. Bisphosphonates and a new class of drugs known as calcimimetics have been used effectively in some patients to control the symptoms of severe hypercalcemia in a palliative setting.

Parathyroid carcinoma: A rare case with mandibular brown tumor

Parathyroid carcinoma constitutes less than 1 % of primary hyperparathyroidism. The male to female ratio is approximately equal and the mean age at presentation is 40 years. In about half of the patients there is a palpable cervical mass, and serum calcium level is usually above 14 mg/dl. In a case report we present a 21-year-old man with a non-tender, non-mobile bulging mandibular mass. He suffered from fatigue, recent weight loss, hoarseness, polydipsia, polyuria, hematuria, recurrent renal stones and bouts of constipation and diarrhea. A mandibular biopsy confirmed brown tumor. Serum calcium level was 15.4 mg/dl. Cervical ultrasound revealed a hypoecho area suspicious of parathyroid adenoma. Parathyroid carcinoma was later confirmed and en bloc resection was performed. During a two-year follow up there has been no evidence of recurrence or hypercalcemia. This unique case of parathyroid carcinoma in conjunction with brown tumor is the second reported case worldwide.

Carcinoma de paratiróide

Carcinoma de paratiróide é uma condição rara, correspondendo na maior parte das casuísticas a menos de 1% dos casos de hiperparatiroidismo primário (HPP). No entanto, pela sua gravidade, e com o prognóstico dependente do diagnóstico precoce e de uma conduta agressiva, é fundamental que a suspeita clínica seja feita pré-operatoriamente. As características clínicas são compatíveis com um caso de HPP grave, sintomático, com tumor cervical >1,5cm, podendo ser palpável. A definição anátomo-patológica pode ser difícil em muitos casos. Nossa casuística (1983-2004) compreende 7 casos, todos sintomáticos, com síndrome hipercalcêmica e doença óssea presente na maioria. Em 6/7 o tumor era palpável, e todos apresentavam quadro bioquímico compatível. Três pacientes faleceram em quadro de hipercalcemia refratária. Dados recentes apontam para uma mutação no gene HRPT2 como base molecular para o desenvolvimento destes tumores. A conduta é cirúrgica e deve incluir hemitiroidectomia e exploração cervical ampliada, procurando focos metastáticos. O pós-operatório é compatível com a gravidade da alteração metabólica pré-existente, sendo comum a tendência a hipocalcemia. O prognóstico de longo prazo depende do diagnóstico precoce, do sucesso cirúrgico e do controle da hipercalcemia. Novas possibilidades terapêuticas, na forma de bisfosfonatos e drogas calcimiméticas, bem como a possibilidade de diagnóstico genético, tendem a melhorar o prognóstico desta grave condição.