The majority of clinically palpable masses affecting the thyroid are benign. Malignant thyroid tumours are the commonest endocrine malignancies yet are rare. Most are of a single distinct cellular type, though mixed cellularity tumours also occur, the commonest of which is papillary and follicular. We describe 2 cases with more than one differentiated tumour in each thyroid gland.
A 44y builder with a family history of medullary carcinoma of the thyroid was found to have a 5cm cystic swelling in the thyroid at screening. FNA showed a cellular follicular lesion. Serum calcium and calcitonin concentrations in a pentagastrin test were normal. An ultrasound showed multiple enlarged lymph nodes. FNA cytology was suggestive of papillary carcinoma. At total thyroidectomy, separate 60mm Hurthle cell tumour and a 7mm mixed follicular and papillary carcinoma were confirmed. Surgery was followed by ablative doses of radioactive iodine and thyroxine suppressive therapy.
A 65 year old Indian woman with a gradually enlarging thyroid mass and obstructive symptoms had a soft 2cm nodule in the right lobe of the thyroid which on FNA showed a Hurthle cell lesion. At surgery, smaller left-sided nodules were noted and shave biopsies taken. Histology demonstrated a completely excised 13mm Hurthle cell tumour and shave biopsies were classical of papillary carcinoma. She subsequently underwent total thyroidectomy with operative cervical lymph node biopsy and later ablative radioactive iodine and thyroxine suppressive therapy. Histology confirmed a 12mm papillary carcinoma with no evidence of lymph node metastases.
These cases illustrate the potential for two separate and histologically distinct tumours to occur within the same thyroid gland. Common sense would suggest that such cases be managed according to the lesion with the worst prognosis.