小松 誠, 藤森 実, 高橋 昭三, 飯田 太

Makoto KOMATSU, Minoru FUJIMORI, Shozo TAKAHASHI, Futoshi IIDA

信州大学医学部第二外科

The Second Department of Surgery, Shishu University School of Medicine

キーワード : Malignant lymphoma of the thyroid, Early detection, Chronic thyroiditis

We describe a patient with malignant lymphoma of the thyroid detected at an early stage by ultrasonography during a follow-up examination for chronic thyroiditis. In October 1989, a 65-year-old male with anterior neck swelling was referred to our department. The ultrasonographic (US) findings of the thyroid were summarized as follows: swollen thyroid including scattered tiny hypoechoic areas and an irregular shaped hypoechoic area measuring 3.4 cm×2.8 cm corresponding to the palpable nodule in the left lobe. The result of aspiration biopsy cytology (ABC) of the left nodule was class III a. At this point, the thyroid was diagnosed as chronic thyroiditis, but the possibility of malignant lymphoma could not be ignored. The nodule of the left lobe measured 1.6 cm×1.6 cm on the US, and the result of ABC of the left nodule was class II in January 1991. The nodule of the left lobe measured 1.2 cm×0.8 cm on the US, and the result of ABC of the left nodule was class II in June 1991. A new hypoechoic area measuring 1.2 cm×1.0 cm appeared in the isthmus, and the result of ABC of the isthmus nodule was class III a. Open biopsy was performed. Malignant lymphoma measuring 1.0 cm existed in the isthmus and the left lobe was chiefly occupied by invading lymphocytes. US was thus useful for early detection of malignant lymphoma of the thyroid during a follow-up examination for chronic thyroditis.