Tago Tomoya, Suzuki Shuji, Kuroda Jun, Udou Ryutaro, Nishida Kiyotaka, Oshiro Yukio, Shimazaki Jirou, Kou Keni, Morishita Yukio, Shimoda Mitsugi
Department of Gastrointestinal Surgery, Tokyo Medical University Ibaraki Medical Center, 3-20-1 Chuo, AmimachiIbaraki, Inashiki-gun, 300-0395, Japan.
Department of Pathology, Tokyo Medical University Ibaraki Medical Center, 3-20-1 Chuo, AmimachiIbaraki, Inashiki-gun, 300-0395, Japan.
Surg Case Rep. 2020 Oct 2;6(1):256. doi: 10.1186/s40792-020-00998-4.
The concept of GIST was established in 1998, clearly differentiating between gastrointestinal leiomyosarcoma and GISTs among gastrointestinal mesenchymal tumors. Lymph node metastasis is extremely rare in true gastrointestinal leiomyosarcoma, and there are no reports of malignant transformation from leiomyoma.
The patient was an old woman who had undergone endoscopic mucosal resection for an Is polyp on the left side of the transverse colon at the age of 73. She was diagnosed with leiomyoma with positive surgical margins. Subsequently, she presented to our institution with a sensation of pressure in the upper abdominal region as a chief complaint at the age of 76 years. Abdominal computed tomography and colorectal endoscopy showed a tumor lesion with invagination of the intestines in the transverse colon, the same site as that of the previously resected leiomyoma. A biopsy suggested a smooth muscle tumor, and we performed partial left transverse colectomy and lymph node dissection under a diagnosis of recurrence and enlargement of the previously incompletely resected leiomyoma. Histopathological examination revealed spindle-shaped tumor cells, and the mitotic activity was 30-40/10 high-power field. Tumor cells were immunohistologically positive for α-smooth muscle actin and h-caldesmon; partially positive for desmin; negative for c-kit, CD34, DOG-1, and the S-100 protein; and showed a Ki-67 labeling index of 70-80%. She was diagnosed with leiomyosarcoma malignantly transformed from leiomyoma. Metastasis was found in 1 of the 14 resected lymph nodes. The patient did not undergo adjuvant chemotherapy, but has survived with no recurrence at 2 years after the surgery.
We have reported a case of leiomyosarcoma of the transverse colon with lymph node metastasis that was malignantly transformed from a leiomyoma.
胃肠道间质瘤（GIST）的概念于1998年确立，明确区分了胃肠道间叶性肿瘤中的胃肠道平滑肌肉瘤和GIST。真正的胃肠道平滑肌肉瘤极少发生淋巴结转移，也无平滑肌瘤恶变的报道。
该患者为老年女性，73岁时因横结肠左侧的Is息肉接受了内镜黏膜切除术。她被诊断为手术切缘阳性的平滑肌瘤。随后，76岁时她因上腹部有压迫感为主诉前来我院就诊。腹部计算机断层扫描和大肠内镜检查显示，横结肠有一处肠套叠的肿瘤病变，与先前切除的平滑肌瘤部位相同。活检提示为平滑肌瘤，我们在诊断为先前切除不完全的平滑肌瘤复发并增大后，进行了左半横结肠部分切除术及淋巴结清扫术。组织病理学检查显示为梭形肿瘤细胞，有丝分裂活性为30 - 40/10高倍视野。肿瘤细胞免疫组织化学检测α - 平滑肌肌动蛋白和h - 钙调蛋白呈阳性；结蛋白部分阳性；c - kit、CD34、DOG - 1和S - 100蛋白阴性；Ki - 67标记指数为70 - 80%。她被诊断为平滑肌瘤恶变的平滑肌肉瘤。在切除 的14枚淋巴结中，有1枚发现转移。患者未接受辅助化疗，但术后2年存活且无复发。
我们报告了1例横结肠平滑肌肉瘤伴淋巴结转移，由平滑肌瘤恶变而来。
