副腎骨髄脂肪腫5例の臨床的検討

Clinical study of five adrenal myelolipoma

　副腎骨髄脂肪腫は，脂肪と骨髄組織から構成される内分泌非活性な良性腫瘍である。今回当科で手術を施行した本症の5例を対象に臨床的検討を行った。男女比は2：3，平均年齢58.4歳，腫瘍の局在は右側が4例と多く，平均腫瘍径は7.8cmであった。画像の特徴は，USで境界明瞭な高エコー腫瘤，CT，MRIでは腫瘍中に脂肪成分が検出されることである。手術は有症状のもの，腫瘍径5cm以上で悪性腫瘍の可能性があるもの，腫瘍径10cm以上で自然破裂による出血の可能性のあるものが適応となる。腫瘍径が小さく無症状なものは経過観察でよいが，腫瘍の増大や症候性になることもあり注意が必要である。

　Adrenal myelolipoma is rare,hormone inactive,benign tumor composed of mature adipose tissue and hematopoietic tissue. From 1996 to 2009,5 patients were operated for adrenal myelolipoma in Jikei University Hospital. Two of them were male and 3 were female. Mean age was 58.4 years old. The tumors were located in the right adrenal in 4 and the left adrenal in 1 patient and mean tumor size was 7.8 cm. Typical imaging features were distinct hyper echoic mass on ultrasonography and intratumoral fatty element by computed tomography and magnetic resonance imaging. All five tumors were removed surgically and myelolipoma was histologically confirmed. Generally,symptomatic tumors,tumors larger than 5 cm with suspected malignancy or tumors larger than 10 cm with possibility of spontaneous rupture should be excised surgically. Asymptomatic small tumors should be observed carefully.