甲状腺混合性髄様濾胞細胞癌の1例

A case of mixed medullary and follicular cell carcinoma of the thyroid

はじめに

　甲状腺乳頭癌，濾胞癌は甲状腺濾胞細胞から生じ，髄様癌は傍濾胞細胞に由来するとされ，その両者が同一腫瘍内で併存することはきわめて稀であり，全甲状腺癌の0.15％と報告されている。1982年に，Hales^1）らにより，髄様癌に濾胞癌が混在した腫瘍が最初に報告されたが，その後の報告数は少なく，いまだその発生のメカニズム，臨床経過については不明な点が多い。今回われわれは，混合性髄様濾胞細胞癌の1例を経験したので報告する。

　The patient was a 59-year-old woman with anterior neck pain. A tumor was observed in the thyroid gland on neck echography, and she was referred to our hospital. A tender 3 cm tumor was palpable in the right lobe of the thyroid gland, causing paralysis of the right vocal cord. The cytological classification of the thyroid tumor was class Ⅴ, and imaging indicated suspected metastasis in the lymph nodes in the lateral neck region. Following the diagnosis of cT4aN1bM0, total thyroidectomy and right neck dissection were performed. In the postoperative pathological diagnosis, a mixture of medullary carcinoma tissue with amyloid deposits and follicular tissue containing colloids. In addition, mixed lesions similar to those of the primary lesion were observed in multiple metastatic cervical lymph nodes. Based on the above findings, the patient was diagnosed with mixed medullary and follicular cell carcinoma. Five years have passed since the operation, but no recurrence has been observed.