Parathyroid carcinoma: biochemical and pathologic response to DTIC

Area of Science:

• Endocrinology
• Oncology
• Surgical Oncology

Background:

• Parathyroid carcinoma is a rare endocrine malignancy causing hyperparathyroidism.
• Complete surgical resection is the primary curative treatment, but local recurrence is common.
• Palliative chemotherapy may be necessary for unresectable or recurrent disease to manage hypercalcemia.

Observation:

• A 33-year-old woman with recurrent functioning parathyroid carcinoma underwent multiple neck explorations.
• The patient received dacarbazine (DTIC) chemotherapy for aggressive, locally recurrent disease.
• Initial DTIC treatment led to significant biochemical improvement (decreased intact parathyroid hormone and serum calcium).

Findings:

• A second course of DTIC resulted in a marked drop in serum calcium but no change in parathyroid hormone levels.
• Autopsy revealed extensive tumor necrosis, suggesting a cytotoxic effect of DTIC.
• The patient ultimately succumbed to complications including septicemia and disseminated intravascular clotting.

Implications:

• This case suggests dacarbazine (DTIC) may have a role in managing recurrent functioning parathyroid carcinoma.
• Aggressive chemotherapy with DTIC early in treatment could be considered given the poor prognosis.
• Further research is warranted to establish the efficacy of DTIC in parathyroid carcinoma.