特发性肠系膜静脉肌内膜增生症临床病理特征

Clinicopathological Features of Idiopathic Myointimal Hyperplasia of Mesenteric Venules

摘要: 目的：探讨特发性肠系膜静脉肌内膜增生症(idiopathic myointimal hyperplasia of mesenteric venules, IMHMV)的临床病理特征与鉴别诊断，提高对该罕见病的认识。方法 收集1例50岁男性结肠IMHMV患者的临床资料、采用HE染色及弹力纤维染色等进行病理学观察，并复习相关文献。结果 患者临床表现为反复腹痛、血便1年余，临床疑诊溃疡性结肠炎。肠镜显示乙状结肠黏膜充血、糜烂伴溃疡形成，因症状持续并出现肠狭窄，行腹腔镜下左半结肠切除术。巨检见肠壁大片不规则溃疡，伴粘膜颗粒样增生及肠腔狭窄。镜检示肠系膜内静脉管壁呈偏心性增厚，致管腔狭窄，内膜下平滑肌细胞显著增生；弹力纤维染色证实病变血管为静脉，伴行动脉正常；周围背景粘膜呈慢性缺血损伤模式，此外，灶性区域粘膜固有层见毛细血管壁增厚(“动脉化”现象)。术后患者未予药物治疗，随访2年无复发。结论 IMHMV是一种罕见的肠道缺血性疾病，确诊依赖于手术标本的病理检查，其特征为静脉肌内膜增生而无其他血管病变。病理医师熟悉其关键形态学特征，给出提示性诊断，避免误诊及指导临床治疗至关重要。

Abstract: Objective: This study aimed to examine the clinicopathological features and differential diagnosis of idiopathic myointimal hyperplasia of the mesenteric venules (IMHMV), with a view to improving recognition of this rare condition. Methods: Clinical data from a 50-year-old male patient with colonic IMHMV were collected. Histopathological examination was conducted using hematoxylin-eosin (HE) staining and elastic fiber staining, and relevant literature was reviewed. Results: The patient presented with recurrent abdominal pain and bloody stools for over one year and was clinically suspected of having ulcerative colitis. Colonoscopy revealed mucosal congestion, erosion, and ulcer formation in the sigmoid colon. Due to persistent symptoms and the development of intestinal stenosis, laparoscopic left hemicolectomy was performed. Gross examination showed extensive irregular ulcers in the intestinal wall, accompanied by mucosal granular hyperplasia and luminal stenosis. Microscopic examination revealed eccentric thickening of the mesenteric venous walls, leading to luminal narrowing, with significant hyperplasia of subendothelial smooth muscle cells. Elastic fiber staining confirmed the affected vessels were veins, while accompanying arteries appeared normal. The surrounding background mucosa exhibited a pattern of chronic ischemic injury. Additionally, focal areas showed thickening of the capillary walls in the lamina propria (“arteriolization”). No postoperative medication was administered, and the patient remained recurrence-free during a 2-year follow-up. Conclusion: IMHMV is a rare ischemic bowel disease, and its diagnosis relies on the pathological examination of surgical specimens. It is characterized by myointimal hyperplasia of the venules in the absence of other vascular pathologies. Familiarity with its key morphological features is crucial for pathologists to provide a suggestive diagnosis, which can help prevent misdiagnosis and guide appropriate clinical management.