Aggressive thyroid cancer associated with toxic nodular goitre.

Reports of concurrent thyrotoxicosis and thyroid cancer have appeared in the last three decades. While most of the tumours have been clinically inconsequential, it has been suggested that thyroid carcinomas arising in patients with Graves' disease tend to behave aggressively, while those associated with toxic nodular goitre follow a more benign course. We report a contrary clinical experience with four cases of thyrotoxicosis associated with metastatic thyroid cancer, two of which were fatal. All four patients had toxic nodular goitre. Thyroid eye signs were uniformly absent. Two patients had received 131I therapy; none had other history of irradiation to the head or neck. Antimicrosomal and antithyroglobulin antibodies were absent in all four patients. Thyroid-simulating immunoglobulin, which was measured in one patient, was also absent. Histopathological examination of the resected thyroid glands revealed two papillary cancers. one mixed anaplastic/papillary and one anaplastic cancer. All four patients had cervical node involvement and one had pulmonary metastases. Both patients with anaplastic carcinoma succumbed to their disease within 6 months: neither of the patients with papillary cancer had disease recurrence after 2 and 4 years, respectively. The experience reported here of aggressive thyroid cancer associated with toxic nodular goitre may represent coincidence or, alternatively, it may represent the early recognition of a change in the natural history of toxic nodular goitre.