Mixed medullary and follicular cell carcinoma of the thyroid with lymph node metastasis in a 7‐year‐old child

A 7‐year‐old boy presented with midline swelling in the neck. On fine‐needle aspiration cytology it was diagnosed as papillary carcinoma of the thyroid. The patient underwent total thyroidectomy. Histopathological examination, immunohistochemistry and electron microscopy revealed the presence of two intermingled components: medullary carcinoma and papillary carcinoma. One of the submandibular lymph nodes had metastasis of both the components. The case was diagnosed as ‘mixed medullary and follicular cell carcinoma’ with papillary carcinoma pattern and lymph node metastasis. Mixed medullary and follicular cell carcinoma with intermingling of medullary and papillary carcinoma components is a rare tumor. In adults, only eight such cases with lymph node metastasis have been published. To the best of the authors’ knowledge no pediatric case has previously been reported in the English‐language literature.