Parathyroid Carcinoma: Report of Three Cases and Review of the Literature

Abstract

Parathyroid carcinoma is a rare endocrine malignancy characterized by the exaggerated metabolic effects of the parathyroid glands. The preoperative differential diagnosis between parathyroid carcinoma and primary hyperparathyroidism is often difficult because many of the signs and symptoms are very similar. Intraoperative differentiation is obscured by the strict anatomic and histologic criteria required for diagnosis of parathyroid carcinoma. We have encountered three patients with parathyroid carcinoma during the last 10 years and managed them successfully. Two of them presented with recurrence of hypercalcemia, one 11 years after and the other 3 years after the primary operation for hyperparathyroidism; both patients were eventually diagnosed with parathyroid carcinoma. The third case was suspected as primary hyperparathyroidism preoperatively but confirmed as carcinoma subsequent to histologic examination.

Parathyroid Cancer - Occurrence, Diagnosis, Treatment

“…The period between the onset of first symptoms and surgical treatment is 3-24 months (mean 9.4) (13,(42)(43)(44)(45)(46)(47)(48).…”

“…Histopathological examinations performed during operative procedure rarely enable explicit assessment of malignancy or diagnosis of PC (12,18,34,44,55,(71)(72)(73)(74)(75)(76)(77)(78)(79)(80)(81)(82)(83)(84)(85)(86). Histopathological diagnosis on postoperative material is also difficult, whereas "final" result is ambiguous and raises doubts among clinicians (12,44,51). In 1973 Schantz and Castelman (20) described histopathological criteria for diagnosing parathyroid cancers.…”

“…The presence of MiB-1 in patients with para- thyroid tumor can indicate a malignant process only and has little effect on postoperative observation or control of the patients (44,59). On the other hand, it is useful to know histological grade of tumor malignancy and its cellular ploidy in order to assess further course of the disease (60).…”

“…Interrelationship between skeletal and renal problems is found in approx. 50% of patients (9,13,44).…”

“…Symptomatic hypercalcemia or skeletal lesions like osteitis fibroso-cystica are not characteristic because they occur also in other malignant diseases accompanied by osteolytic metastases to bones (44). Differentiation between IHP and advanced PC is still more perplexing if the latter has ectopic localization (6,34).…”