腎周囲を原発とした混合型脂肪肉腫

Retroperitoneal mixed-type perinephric liposarcoma：A case report

症例は66歳男性。2009年7月頃より腹部膨満感を自覚していた。4年前と今回の画像所見から，腎周囲を原発とした脂肪肉腫と診断し，後腹膜腫瘍切除術，根治的腎摘除術を施行した。腫瘍は径32×30cm，切除重量は5.88kg，病理診断は高分化型と脱分化型とが混合した脂肪肉腫であった。術後療法は行わず経過観察しているが，再発は認めていない。

A 66-year-old man,with abdominal distention,was referred to our department for the treatment of an abdominal tumor. Contrast computed tomogram and magnetic resonance imaging revealed a large retroperitoneal fatty tissue mass with calcification measured about 25 cm in diameter. The tumor,displacing the jejunum and the descending colon,was diagnosed as a liposarcoma. The previous contrast computed tomogram showed the abnormal signal in the left renal capsule,suggesting that the tumor was originated from the perinephric tissue. A complete excision of the tumor with concomitant resection of the left kidney was performed in September,2009. The tumor did not involve other organs and weighed 5.88 kg. Histological examination disclosed retroperitoneal mixed-type liposarcoma composed of well-differentiated and dedifferentiated type. The patient did not consent to receive any adjuvant therapy. Neither local recurrence nor metastasis has been seen at 5 months after the operation.