Endocrine Abstracts

Introduction: Differentiated thyroid carcinoma (papillary and follicular) being the most common type of thyroid malignancy (80%), originates from the thyroglobuline secreting follicular cells. Medullary thyroid cancer derived from parafollicular C-cells producing calcitonin is relatively rare (5–10%). In this report we aimed to present a case with simultaneous papillary and medullary carcinoma in the same thyroid nodule.

Case report: Sixty nine year old woman admitted with progressive swelling on the right side of the neck. Her past medical history was unremarkable except for well controlled hypertension. She had no radiotherapy exposure to neck and family history was negative for thyroid malignancy. Thyroid function tests were euthyroid. Her neck ultrasonography revealed multinodular goiter and right submandibular solid mass. Fine needle aspiration biopsy of the right dominant 14 mm hipoechoic thyroid nodule and right submandibular mass revealed papillary carcinoma and pleomorphic adenoma respectively. She underwent total thyroidectomy and right suprahyoid neck disection. Pathology was reported as pleomorphic adenoma (submandibular gland), medullary thyroid carcinoma and focal papillary thyroid carcinoma (14×12 mm) (right thyroid nodule). She recieved radioactive iodine ablative therapy. She is currently on follow up in remission state.

Conclusion: The coexistance of different malignancies within the same mass is termed as ‘collision tümör’. Appearance of concurrent papillary and medullary pathological features in the same thyroid tumor, so-called ‘collision tumor’ of the thyroid, is relatively rare being less than 1% of the all thyroid malignancies. There are no pathogenetic mechanisms available so far to explain the concomitant neoplastic transformation of the C-cells and follicular cells in the same thyroid nodule. Further analyses are needed to detect the etiopathogenesis of this condition.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.

Figure 1 Microscopic appearance of adjacent papillary (P) and medullary (M) thyroid carcinoma.