Coexistence of Medullary Carcinoma and Papillary Carcinoma in the Same Lobe of the Thyroid: A Rare Case Report

We report a rare case of coexistence of medullary thyroid carcinoma (MTC) and papillary thyroid carcinoma (PTC) in the right thyroid lobe. A 60-year-old female patient was diagnosed with MTC and PTC after right hemithyroidectomy. The extreme rarity of this pathological feature is discussed. While immunohistochemistry for calcitonin and thyroglobulin suggested histogenesis, cytopathology of the biopsy confirmed MTC and PTC. The coexistence of MTC and PTC differs from the most common mixed tumours as both tumors occurred in the single tissue. In conclusion, this case report not only can improve the clinical diagnosis rate of rare cases, but also can avoid reoperation of the patients, and improve survival and the quality of life.