PET検査により偶然に発見された精巣悪性リンパ腫

Positron emission tomography incidentally discovered testicular malignant lymphoma

症例は76歳，男性。顔面神経麻痺を主訴に当院神経内科に紹介された。FDG-PET検査を施行したところ，陰囊内に集積がみられ紹介を受けた。両側精巣には，触診上・超音波検査上ともに異常所見はなかった。自覚症状はなく，精巣腫瘍に関連した腫瘍マーカーも基準値以内であったため経過観察とした。約1か月後，左精巣は右に比べてやや硬く腫大していた。精巣腫瘍の診断で高位精巣摘除術を施行した。病理診断はdiffuse large B-cell lymphomaであった。

　A 76-year-old male with facial paralysis, found to have abnormal left lung shadow on computed tomography. Positron emission tomography was performed, and there were accumulations in the left lung region and scrotum. On the first visit in our department, there was no laterality in the testicular size on palpation, and no laterality observed on ultrasonography. The patient had no local subjective symptom, therefore a close course observation was selected. About one month later, the left testis because slightly swollen and hard, high inguinal orchiectomy was performed. The tumor was diagnosed as diffuse large B-cell lymphoma. The abnormal shadow in the lung and facial paralysis may have been due to lymphoma and paraneoplastic neurological syndrome. It may be rare but possible for PET to detect tumor even when the tumor is still in an early stage.