Mesenteric fibromatosis (MF) is a proliferative fibroblastic lesion of the intestinal mesentery. It constitutes 8% of all desmoid tumors, representing 0.03% of all neoplasms. It is benign histologically, although it could infiltrate locally and recur following excision; however, it is free from the potential to metastasize. It is spontaneous or associated with familial adenomatous polyposis (FAP]) mutation as a part of Gardner's syndrome. This case report discusses the radiological, intraoperative, and histopathological findings from a 45-year-old male patient who presented with abdominal pain and a palpable mass in the left hemiabdomen. The pain was dull and aching, extending to the back and unrelated to any other gastrointestinal symptoms. There was no history of severe weight reduction. Furthermore, he is not a smoker. There were no comorbidities, severe medical diseases, or prior surgical procedures. Computerized tomography revealed a well-defined, lobulated, heterogeneously enhancing altered signal intensity mass at the mesocolon. Ultrasonography of the abdomen showed an intra-abdominal mass. Macroscopic mass characteristics include a well-defined mass measuring 22 × 14 × 11 cm connected to a small intestine segment measuring 21 × 2 × 2 cm. Histopathological and immunohistochemical examinations of the resected tumor, including positive nuclear immunostaining for beta-catenin, confirmed a postoperative diagnosis of desmoid-type fibromatosis. Based on its clinical presentation and computed tomography results, this case demonstrated how desmoid-type fibromatosis of the colon might mimic gastrointestinal stromal tumors (GISTs). Due to the varied therapies and follow-up methods used for these lesions, the differential diagnosis between desmoid-type fibromatosis and GIST is clinically significant.

中文翻译：

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模仿胃肠道间质瘤的左侧结肠系膜侵袭性纤维瘤病：病例报告。

肠系膜纤维瘤病（MF）是肠系膜的增殖性成纤维细胞病变。它占所有硬纤维瘤的 8%，占所有肿瘤的 0.03%。它在组织学上是良性的，尽管它可能局部浸润并在切除后复发；然而，它没有转移的潜力。它是自发的或与作为加德纳综合征一部分的家族性腺瘤性息肉病 (FAP]) 突变相关。本病例报告讨论了一名 45 岁男性患者的放射学、术中和组织病理学结果，该患者出现腹痛和左半腹部可触及肿块。疼痛呈钝痛，延伸至背部，与任何其他胃肠道症状无关。无严重体重减轻史。此外，他不吸烟。没有合并症、严重的内科疾病或既往外科手术。计算机断层扫描显示结肠系膜处有一个边界清晰、分叶状、不均匀增强的信号强度改变的肿块。腹部超声检查显示腹内有肿块。宏观肿块特征包括尺寸为 22 × 14 × 11 厘米的明确肿块，与尺寸为 21 × 2 × 2 厘米的小肠段相连。切除肿瘤的组织病理学和免疫组织化学检查，包括β-连环蛋白核免疫染色阳性，证实了硬纤维瘤型纤维瘤病的术后诊断。根据其临床表现和计算机断层扫描结果，该病例证明了结肠硬纤维瘤型纤维瘤病可能与胃肠道间质瘤 (GIST) 相似。由于这些病变采用的治疗方法和随访方法各不相同，硬纤维瘤型纤维瘤病和胃肠道间质瘤之间的鉴别诊断具有临床意义。