急速な増大を認めた後腹膜Inflammatory fibrosarcomaの1例

Abstract

65歳女。顕微鏡的血尿を主訴とした。DIP, 腹部CT, MRI各所見にて右腎部に類円形の充実性腫瘍(径64×55×71mm)を認め, 腎被膜発生の腎血管筋脂肪腫, 腎細胞癌, 腎周囲組織発生の悪性線維性組織球症を疑った。手術直前のCTにて腫瘍の急激な増大(径110×80×82mm)と貧血の進行を認めたため, 腎血管筋脂肪腫の自然破裂を疑い経腹的根治的右腎摘除術を行った。腫瘍は周囲組織と癒着しておらず, 石様硬, 割面は灰白色で, 血腫や壊死を認めなかった。病理組織学的所見より, 後腹膜由来のinflammatory fibrosarcomaと診断した。術後, 検査値は正常となり, 術後3ヵ月現在で再発転移は認めない。

A 65-year-old woman presented with microscopic hematuria. Computed tomography (CT) and magnetic resonance imaging revealed a solid tumor measuring 64 x 55 x 71 mm adjacent to the right kidney. After 51 days, the CT demonstrated progressive enlargement of the tumor (110 x 80 x 82 mm), and the tumor-doubling time was calculated as 33 days. A transperitoneal right radical nephrectomy was performed. Histologically, the tumor was arising from retroperitoneum and consisted of variable arranged spindle cell proliferation with an infiltration of inflammatory cells. Immunostaining examination showed positive staining for alpha-smooth muscle actin (SMA), vimentin, cytokeatins, and CD 68, whereas desmin, CD 34, and p53 were negative. High proliferative activity (20%) was demonstrated by MIB1 immunostaining. Then the tumor was diagnosed as inflammatory fibrosarcoma. The patient has been followed up for 3 months since the operation with no evidence of local recurrence or distant metastasis.