高CT値を示した単純性腎嚢胞

A CASE OF HYPERDENSE RENAL CYST DIFFICULT TO MAKE PREOPERATIVE DIAGNOSIS

　45歳，男性．本邦5例目の高CT値腎嚢胞の1例を報告した．右側腹部痛を主訴として当科受診．超音波検査，DIP,CTならびに血管造影から，後腹膜の嚢胞性疾患が疑われたが，充実性腫瘤も否定し得なかったため，手術を施行したところ，右腎嚢胞が確認され，高CT値腎嚢胞であることが判明した．本症例は，CTのみならず超音波検査でも充実性病変様の所見が認められたために，術前診断が困難であった．

A case of hyperdense renal cyst in a 45-year old man is reported. The patient was admitted to our department, complaining of dull right flank pain. Both ultrasonogram and CT scan revealed a solid mass of the lower pole of the right kidney, which was shown avascular by angiography. So, we performed an operation under the diagnosis of retroperitoneal solid tumor, but the lesion proved to be a simple renal cyst. Histopathological studies revealed no evidence of malignancy in the cyst wall. This case seems to be the 5th presentation of a hyperdense renal cyst in Japan.