早期から多発骨転移を認めた腎粘液管状紡錘細胞癌の1例

Renal mucinous tubular and spindle cell carcinoma （pT1a） combined with synchronous multiple bone metastasis：a case report

mucinous tubular and spindle cell carcinoma（MTSCC）は2004年にWHO分類に追加された比較的新しいまれな腎腫瘍であり，その臨床予後などはいまだ十分な知見が得られていない。今回我々は，MTSCCが発見時局所pT1aであったにもかかわらず同時性多発骨転移を伴っていた症例を経験したため，文献的考察を合わせて報告する。

We present the case of a male in his 70s incidentally diagnosed with a high–grade mucinous tubular and spindle cell carcinoma of the left kidney, combined with synchronous bone metastasis. The renal tumor was 1.5 cm–diameter, showed hypovascular mass without capsule on dynamic enhanced CT. Preoperative diagnosis was difficult because the tumor had little mucin content resulting in heterologous hypointense signal on T2 weighted image. Synchronous metastasis from pT1a renal cell carcinoma is uncommon, but can occur in poorly differentiated tumors, frequently targeting bones.