Parathyroid Carcinoma

• • Associated with profound hypercalcemia

Epidemiology

• • Found in 0.5-1% of patients with hyperparathyroidism

  • Cancer is palpable in 50% of the patients

  • 5% of parathyroid cancers are nonfunctional

  • Patients with parathyroid cancer are on average younger at the time of diagnosis than patients with benign hyperparathyroidism

  • Equal distribution among men and women

Symptoms and Signs

• • Palpable neck mass

  • Hoarseness

  • Fatigue, depression, nausea, vomiting, dehydration, polydipsia, polyuria

  • Pathologic fractures

  • Nephrolithiasis (70% of patients)

  • Nephrocalcinosis

  • Severe renal dysfunction (20-50% of patients)

  • Pancreatitis and peptic ulceration (10-15% of patients)

Laboratory Findings

• • Profound hypercalcemia

  • Elevated intact parathyroid hormone (PTH)

• • Parathyroid carcinoma is suspected at operation if parathyroid is hard, whitish, has an irregular capsule, or is invasive

  • Rarely diagnosed preoperatively

• • Physical exam

  • PTH and calcium levels

  • Chest and neck CT scan

• • Anecdotal evidence for role of radiation therapy in local control of disease

Surgery

• • Surgical resection is mainstay of treatment

  • En bloc resection should be carried out where possible (including ipsilateral thyroid lobe and central compartment lymph nodes)

  • Resection of local recurrent or metastatic disease is recommended if possible

Indications

• • All parathyroid carcinomas should be resected

Radiation

• • Anecdotal evidence for role of radiation therapy in local control of disease

Medications

• • Palliative drug: IV bisphosphonate to maintain eucalcemia

Treatment Monitoring

• • Physical exam

  • Serum calcium and intact PTH levels

Prognosis

• • Indolent malignancy, with local and distant metastases occurring over many years

  • 5-year survival rates range from 40% to 69%

References