Int J Gynecol Pathol. 2023 Sep 1;42(5):451-459. doi: 10.1097/PGP.0000000000000926. Epub 2022 Dec 1.
The majority of inflammatory myofibroblastic tumors (IMTs) in the gynecologic tract occur in the uterine corpus and harbor anaplastic lymphoma kinase ( ALK ) rearrangement. Herein, we report 1 uterine IMT case with a novel fusion involving ALK and 1 uterine IMT case with ROS1 rearrangement. The ages of the patients were 56 and 57 yr, respectively. The tumor size was 10.0 and 8.0 cm, respectively. Both patients had stage IB disease. Histologically, the 2 IMT cases had classic morphologic features and predominantly comprised bland spindle cells with hypercellular (fascicular/storiform) and hypocellular (myxoid rich) areas admixed with variably prominent lymphoplasmacytic infiltration. Immunohistochemically, the ALK -rearranged case was positive for ALK , and the ROS1 -rearranged case was positive for ROS1 . Both cases were diffusely positive for desmin. The tumor cells were variably positive for estrogen receptor (1/2 cases, 50.0%) and progesterone receptor (1/2 cases, 50.0%). Targeted RNA sequencing revealed one case each with either a novel CASC15-ALK or TFG-ROS 1 fusion. We identified a novel ALK fusion partner CASC15 in IMT and described the first uterine IMT with a TFG-ROS1 fusion. This study improves our understanding of molecular events in IMT.
大多数妇科生殖道炎性肌纤维母细胞瘤（IMT）发生于子宫体，具有间变性淋巴瘤激酶（ALK）重排。本文报道了 1 例伴有新型 ALK 融合的子宫 IMT 和 1 例伴有 ROS1 重排的子宫 IMT。患者年龄分别为 56 岁和 57 岁，肿瘤大小分别为 10.0cm 和 8.0cm，均为 IB 期。2 例 IMT 组织学上均具有典型形态学特征，主要由温和的梭形细胞组成，伴不同程度的淋巴浆细胞浸润，具有丰富的细胞性（束状/席纹状）和细胞稀疏区（黏液样）。免疫组化染色，ALK 重排的病例 ALK 阳性，ROS1 重排的病例 ROS1 阳性。2 例均弥漫性 desmin 阳性。肿瘤细胞不同程度地表达雌激素受体（2 例中的 1 例，50.0%）和孕激素受体（2 例中的 1 例，50.0%）。靶向 RNA 测序显示各有 1 例分别具有新型 CASC15-ALK 或 TFG-ROS1 融合。我们在 IMT 中鉴定出新型 ALK 融合伙伴 CASC15，并描述了首例具有 TFG-ROS1 融合的子宫 IMT。本研究提高了我们对 IMT 中分子事件的认识。
