Kataoka Tatsuki R, Yamashita Nobuhiro, Furuhata Ayako, Hirata Masahiro, Ishida Takaki, Nakamura Ichiro, Hirota Seiichi, Haga Hironori, Katsuyama Eiji
Department of Diagnostic Pathology, Kyoto University Hospital, Sakyo-ku, Kyoto 606-8507, Japan.
World J Surg Oncol. 2014 Jun 18;12:186. doi: 10.1186/1477-7819-12-186.
Inflammatory myofibroblastic tumors (IMTs) and gastrointestinal stromal tumors (GISTs) are both spindle cell tumors, and occur rarely in the wall of the urinary bladder. In general, immunostaining allows differentiation of IMTs and GISTs. Most IMTs are positive for anaplastic lymphoma kinase (ALK) and negative for KIT, whereas most GISTs are ALK-negative and KIT-positive. Here, we describe a case of a spindle cell tumor in the wall of the urinary bladder. The spindle cells were positive for both ALK and KIT, and it was thus difficult to determine whether the tumor was an IMT or a GIST. We eventually diagnosed an IMT, because ALK gene rearrangement was confirmed by fluorescent in-situ hybridization. Cytoplasmic staining for KIT and the absence of other GIST markers, including DOG1 and platelet-derived growth factor α, indicated that the tumor was not a GIST. Therefore, IMTs should be included in the differential diagnosis of spindle cell tumors, even those that are KIT-positive.
炎性肌纤维母细胞瘤（IMTs）和胃肠道间质瘤（GISTs）均为梭形细胞瘤，很少发生于膀胱壁。一般来说，免疫染色可用于区分IMTs和GISTs。大多数IMTs间变性淋巴瘤激酶（ALK）呈阳性，KIT呈阴性，而大多数GISTs ALK呈阴性，KIT呈阳性。在此，我们描述一例膀胱壁梭形细胞瘤病例。梭形细胞ALK和KIT均呈阳性，因此难以确定该肿瘤是IMT还是GIST。我们最终诊断为IMT，因为荧光原位杂交证实了ALK基因重排。KIT的细胞质染色以及其他GIST标志物（包括DOG1和血小板衍生生长因子α）的缺失表明该肿瘤不是GIST。因此，IMTs应纳入梭形细胞瘤的鉴别诊断，即使是那些KIT阳性的肿瘤。
