Anaplastic lymphoma kinase(ALK)免疫染色が診断に必要であった膀胱の炎症性筋線維芽細胞性腫瘍(Inflammatory myofibroblastic tumor)の1例

Abstract

52歳女.患者は排尿時痛を主訴とした.腫瘍マーカーは正常範囲内であったが, 膀胱鏡所見では左後三角部に径3cm, 周囲に浮腫を伴う充実性非乳頭状腫瘍が認められた.更にMRIでは腫瘍はT1, T2強調画像ともに低信号で描出され, 造影効果が強く, 膀胱筋層への浸潤が認められた.病理組織学的所見では一部に上皮成分を混じえた大型の異型紡錘形細胞の浸潤性増生を認め, 膀胱肉腫様癌(cT2bN0m0)と診断された.前方骨盤内臓全摘・導尿型新膀胱造設術を施行したところ, 全摘標本の病理組織学的所見は紡錘形細胞の増生を認めたが, 上皮細胞の増殖は認めなかった.紡錘形細胞はcytokeratin, vimentin, smooth muscle actinに加え, anaplastic lymphoma kinase(ALK)も陽性で, 膀胱の炎症性筋線維芽細胞性腫瘍と確診された.術後1年経過現在, 再発は認められていない

A 52-year-old house wife presented with pain on urination. Cystoscopy and magnetic resonance imaging revealed solid and sessile tumor of 3 cm in diameter invading the bladder wall. Pathological examination of the transurethral resection specimen showed proliferation of spindle cells and epithelial cells. Since both types of cells were positive for cytokeratin immunostaining, sarcomatoid carcinoma was highly suspected. She underwent anterior pelvic exenteration and construction of continent reservoir (Penn Pouch). Since the tumor cells showed spindle cell proliferation alone without epithelial growth and positive staining for anaplastic lymphoma kinase, we corrected the final diagnosis as an inflammatory myofibroblastic tumor of the urinary bladder. She has been doing well without recurrence for 1 year.