Son Seung-Myoung, Woo Chang Gok, Lee Ok-Jun, Kim Yong June, Lee Ho-Chang
Department of Pathology, Chungbuk National University Hospital, Chungbuk National University College of Medicine, Cheongju, North Chungcheong 28644, Republic of Korea.
Department of Urology, Chungbuk National University Hospital, Chungbuk National University College of Medicine, Cheongju, North Chungcheong 28644, Republic of Korea.
Oncol Lett. 2023 Apr 13;25(6):227. doi: 10.3892/ol.2023.13813. eCollection 2023 Jun.
Inflammatory myofibroblastic tumors (IMTs), which are rare tumors, exhibit myofibroblastic differentiation, often with anaplastic lymphoma kinase (ALK) gene rearrangements. A subset of IMTs identified in the urinary tract have been shown to harbor a fibronectin 1 (FN1)-ALK gene fusion. In this case report, a case of an IMT with FN1-ALK fusion in the urinary bladder was presented, and its clinicopathological characteristics were reviewed. A 45-year-old female was referred to Chungbuk National University Hospital with gross hematuria. Cystoscopy revealed a solid mass in the bladder. The patient subsequently underwent transurethral resection of the lesion. The mass comprised stellate and spindled myofibroblastic cells that were arranged in loose fascicles, with a myxoid background and a mixed inflammatory infiltrate. Immunohistochemical analysis revealed that the tumor cells were positive for vimentin, cytokeratin AE1/AE3 and ALK, and focal-positive for desmin. Targeted next-generation sequencing was subsequently employed to identify the FN1-ALK fusion. To date, the patient has undergone outpatient follow-up for 18 months, with no signs of tumor recurrence. To conclude, in total, FN1 has been identified as an ALK fusion partner almost exclusively in cases of genitourinary IMTs [13 bladder IMTs (including the present case) and two uterine IMTs]. In the present case, the FN1-ALK fusion was found to involve ALK exon 19 and FN1 exon 23. By contrast, the majority of the other IMTs with an ALK fusion have involved ALK exon 20, whereas ALK fusion involving ALK exon 18 or 19 has been reported only in genitourinary IMTs. Therefore, the FN1-ALK fusion involving ALK exon 18 or 19 may be specific to a subset of IMTs arising in the urinary bladder.
炎性肌成纤维细胞瘤（IMTs）是一种罕见肿瘤，具有肌成纤维细胞分化特征，常伴有间变性淋巴瘤激酶（ALK）基因重排。已证实在泌尿道中发现的一部分IMTs含有纤连蛋白1（FN1）-ALK基因融合。在本病例报告中，呈现了1例膀胱中存在FN1-ALK融合的IMT病例，并对其临床病理特征进行了回顾。一名45岁女性因肉眼血尿被转诊至忠北国立大学医院。膀胱镜检查发现膀胱内有一实性肿块。该患者随后接受了经尿道病变切除术。肿块由星状和梭形肌成纤维细胞组成，这些细胞排列成疏松束状，伴有黏液样背景和混合性炎性浸润。免疫组织化学分析显示肿瘤细胞波形蛋白、细胞角蛋白AE1/AE3和ALK呈阳性，结蛋白呈局灶性阳性。随后采用靶向二代测序来鉴定FN1-ALK融合。迄今为止，该患者已接受门诊随访18个月，无肿瘤复发迹象。总之，总共已确定FN1几乎仅在泌尿生殖系统IMT病例中作为ALK融合伴侣[13例膀胱IMT（包括本病例）和2例子宫IMT]。在本病例中，发现FN1-ALK融合涉及ALK外显子19和FN1外显子23。相比之下，其他大多数具有ALK融合的IMTs涉及ALK外显子20，而涉及ALK外显子18或19的ALK融合仅在泌尿生殖系统IMTs中有报道。因此，涉及ALK外显子18或19的FN1-ALK融合可能是膀胱中出现的一部分IMTs所特有的。
