Parathyroid carcinoma and oxyphil parathyroid adenoma: an uncommon case of misinterpretation in clinical practice.

A 46 year-old male presented with persistently high level of serum parathyroid hormone (PTH), despite successful resection of an oxyphilic cell parathyroid adenoma of the left lower gland. Renal function and serum calcium were normal, leading to vitamin D deficiency being considered. Tc99m-sestamibi parathyroid scintigraphy showed no capitation, but a cervical ultrasound demonstrated an increase in the lower parathyroids. Surgery confirmed that the right gland was normal but the left corresponded to parathyroid carcinoma. The patient developed severe hypocalcemia, with PTH values being consistent with hypoparathyroidism for a few months. However, a progressive increase in calcium and PTH serum levels indicated recurrence of disease. Tc99m-sestamibi scintigraphy demonstrated hyperfixation in topography of the left inferior parathyroid and the patient was subjected to a third and more extensive surgery, with removal of lymph nodes and adjacent thyroid tissue. Serum calcium and PTH remained elevated, requiring loop diuretics and intravenous bisphosphonates to control hypercalcemia. Cervical radiotherapy was implemented as adjuvant therapy. After two months the patient complained of dyspnea, and a CT scan of the chest demonstrated areas of parenchymal condensation, suggestive of actinic pneumonitis. At the 2-year follow-up no major issues were evident.

Mediastinal parathyroid carcinoma presenting with severe skeletal manifestations.

Parathyroid carcinoma is a rare malignancy, accounting for about 1% of primary hyperparathyroidism. We report the case of a 23-year-old man who presented with poorly united mid-shaft fracture of the left femur with severe hypercalcaemia in the setting of 99 mTc sestamibi-avid lesions in the mediastinal and thoracic vertebrae. The patient underwent surgery, and histopathology revealed a low-grade parathyroid carcinoma. After surgery, the patient developed severe hungry bone syndrome requiring intensive calcium, magnesium and active vitamin D supplementation. A review of the literature was undertaken with regards to mediastinal parathyroid carcinoma, management of refractory hypercalcaemia in this setting and hungry bone syndrome.

[Hyperparathyroidism--new aspects]. / Neue Aspekte bei Hyperparathyreoidismus.

Hyperparathyroidism is generally classified into a primary and secondary form. The primary form is caused by an autonomous adenomatous hypertrophy and/or hyperplasia of parythyroideal glands without known cause in most of the patients. Resulting elevated levels of parathyroid hormone cause elevation of serum calcium, subsequently followed by cerebral symptoms, fatigue and calcinosis of vessels and kidneys. The mainstay of secondary HPT is the initial vitamin D deficiency such as associated with kidney failure. Via an increased PTH secretion, calcium homeostasis will be maintained together with ongoing hyperplasia of the parathyroidea. Therapeutic approaches are related to pathophysiological mechanisms. While surgical removal of adenomatous glands is the mainstay of therapy in primary and late secondary forms, during the still regulated initial period of secondary HPT supplementation of vitamin D and/or sensitation of parathyroideal Calcium-sensing-receptors are therapy of choice.

Positive effect of radiotherapy and surgery on hormonally active pulmonary metastases of primary parathyroid carcinoma.

OBJECTIVE: Parathyroid carcinoma is a rare cause of primary hyperparathyroidism. Surgery is the primary treatment in recurrent or metastatic disease. Radiotherapy has been used as an adjuvant to control subclinical local disease but is otherwise considered ineffective. DESIGN: We report on a patient with parathyroid carcinoma with hypercalcaemia and pulmonary metastases, treated with pamidronate and radiotherapy and later with surgery. METHODS: The treatment was evaluated using serial analysis of serum parathyroid hormone (PTH) and calcium, clinical evaluation and chest radiographs. RESULTS: Intravenous pamidronate alone had limited effect on hypercalcaemia. Following irradiation of the pulmonary lesions (34 Gy in ten fractions), serum levels of calcium and PTH decreased and pamidronate could be discontinued. The patient's general condition improved parallel to a radiological response. At clinical relapse 18 months following radiotherapy, the pulmonary metastases were resected and serum PTH was normalised. CONCLUSIONS: The results indicate that parathyroid carcinoma can be radiosensitive. Thus radiotherapy may be an alternative to palliate symptoms of hypercalcaemia in patients not suited for surgery.

Absence of response to human parathyroid hormone in athymic mice grafted with human parathyroid adenoma, hyperplasia or parathyroid cells maintained in culture.

In athymic mice we have developed a model of long-term human PTH hypersecretion, using xenotransplantation of respectively parathyroid gland fragments obtained from patients with primary (primary) or secondary (secondary) uremic hyperparathyroidism (HPT), and parathyroid cells maintained in culture from patients with secondary uremic HPT. Both grafted parathyroid tissue fragments and cultured cells induced prolonged and marked secretion of human intact PTH (iPTH) in nude mice. Despite extremely high plasma iPTH levels, hypercalcemia or hypophosphatemia was not observed. Moreover, PTH secretion was not significantly modified by low-calcium, high-phosphate diet for 3 weeks. Four mice which had a mean plasma human iPTH level of 237+/-152 pg/ml for more than 9 months and 4 age-matched, sham-grafted control mice with undetectable human iPTH levels underwent bone histomorphometry examination. No difference was found between the two groups with respect to active bone resorption surface or number of osteoclasts/mm2. We hypothesize that the characteristic deficit of T cell function and of cytokine and growth factor production may protect nude mice with chronic hypersecretion of human PTH from hypercalcemia and bone lesions. We suggest that this strain of mice could be used for better understanding the relationship between cytokines and bone turnover.

Functioning parathyroid lipoadenoma--report of four cases: clinicopathological and ultrasonographic features.

Functioning parathyroid lipoadenoma (hamartoma) composed of abundant adipose or myxomatous stroma and epithelial cell nests is an unusual cause of primary hyperparathyroidism. We report herein four new cases. None of them belongs in the category of multiple endocrine neoplasia or familial hyperparathyroidism. The clinical manifestations and the laboratory findings are indistinguishable from those of the usual forms of primary hyperparathyroidism. Ultrasonography of the neck demonstrated an enlarged parathyroid gland as a hyperechoic mass in the two patients tested. At operation in each case, a single enlarged gland was found and resected, the weight being 3, 0.3, 0.45 and 1 g, respectively. The patients are normocalcemic 1 to 10 years after surgery. Pathological examination disclosed that the lesions were consistent with lipoadenoma or its variants. On reviewing 20 cases of functioning lipoadenoma which were reported in the literature, including the present cases, we found that the size of the tumors varied and a functioning lipoadenoma is hence by no means unusually large as previously reported. Without knowledge of this specific clinicopathologic entity, the lesion may be overlooked at the preoperative localization study and misdiagnosed as a normal or hyperplastic parathyroid.