Simultaneous medullary carcinoma, papillary carcinoma and granulomatous inflammation of the thyroid

Thyroid tumours with both papillary and medullary carcinoma features are rare and represent less than 1% of all thyroid malignancies. These tumours have a different clinical presentation and biological behaviour from tumours that have only papillary or medullary carcinoma features. The phenomenon of mixed thyroid tumours can be observed in two settings--a mixed tumour showing dual differentiation, or a collision tumour. For a precise diagnosis of this rare mixed thyroid carcinoma, fine needle aspiration cytology results should be correlated with serum calcitonin and thyroglobulin levels. The diagnosis should also be confirmed using immunocytochemistry. Surgery is the treatment of choice, and the role of postoperative radioiodine is controversial. We herein report the case of a 35-year-old man with a mixed medullary-papillary carcinoma of the thyroid, which presented with C-cell hyperplasia, granulomatous inflammation and metastasis to the cervical lymph nodes. The patient was treated with total thyroidectomy and nodal clearance. This case highlights the need for awareness of coexistent entities as they warrant separate treatments.