Papillary thyroid carcinoma combined with thyroid mucosa-associated lymphoid tissue (MALT) lymphoma is exceedingly rare and there is no standard management.

We report a rare association of MALT lymphoma of thyroid in a 60-year-old woman with Hashimoto's thyroiditis along with an incidental focus of papillary carcinoma.

Patients with Hashimoto's thyroiditis are prone to develop other thyroid pathology, including rare tumours such as MALT lymphoma. The differential diagnosis for a neoplasm in such patients should be wide.

Thyroid nodules are frequently present in Graves' disease. The aim of this study was to evaluate the risk of thyroid carcinoma in Graves' disease patients, with and without ultrasonographically identified nodules, who subsequently underwent surgical treatment.

The study group included 150 consecutive patients with diagnosed Graves' disease who subsequently underwent surgery.

The patients were divided into two groups according to whether the pre-operative ultrasound scan showed diffuse parenchyma (group one; n = 70) or nodules (group two; n = 80).

Of the 150 patients, 18 (12 per cent) were found to have papillary thyroid carcinoma. Papillary carcinoma was found in seven patients (10 per cent) in group one and in 11 patients (1.7 per cent) in group two. After evaluating the overall groups, the incidence of carcinoma in the parenchyma outside a nodule was 67 per cent, whereas the incidence of carcinoma in a nodule was 33 per cent.

Carcinoma can occur in Graves' disease patients without nodules, and the absence of nodules on ultrasonographic examination does not reduce the risk of malignancy.