Morishita Shigemi, Yoshida Shinichi, Kamatani Yasufumi, Suzuhigashi Shinya, Kitou Masaki, Nasu Takuma
Department of Surgery, Kagoshima Seikyou General Hospital, 5-20-10 Taniyama-chuou, Kagoshima City, Kagoshima, 891-0141, Japan.
Department of Pathology, Kagoshima Seikyou General Hospital, 5-20-10 Taniyama-chuou, Kagoshima City, Kagoshima, 891-0141, Japan.
Surg Case Rep. 2022 Aug 1;8(1):146. doi: 10.1186/s40792-022-01482-x.
The prevalence and incidence of neuroendocrine tumors (NETs) are increasing worldwide. Primary mesenteric NETs are extremely rare. Solid tumors that arise in the mesentery are typically metastatic. We present an extremely rare case of a primary grade 2 NET (NET G2) in the ileal mesentery.
A 54-year-old man was referred to our hospital for further examination of a previously diagnosed right mesenteric tumor. Mild tenderness was noted on the right side of the abdomen, but there were no palpable masses. Fluorodeoxyglucose-positron emission tomography (FDG-PET) revealed slight FDG uptake (maximum standardized uptake value, 2.0) in the right abdomen, and a benign or low-grade malignant tumor was suspected. We extracted the ileal mesenteric tumor with an ileal resection (90 cm). The cut surface of the 55 × 33 × 33 mm tumor was pale yellowish-white. Immunohistochemistry revealed diffuse staining for synaptophysin and chromogranin A, and focal staining for CD56. The Ki-67 index was 3%. The final pathological diagnosis was NET G2. The patient's postoperative course was uneventful, and he developed no recurrence 1.5 years after surgery. Postoperative antitumor therapy was not performed for this patient because the histological diagnosis was NET G2, and it was determined that the tumor could be completely resected by surgery.
We report an extremely rare case of primary ileal mesenteric NET. Mesenteric tumors that show slight FDG uptake on FDG-PET examination should be considered well-differentiated NET.
神经内分泌肿瘤（NETs）在全球范围内的患病率和发病率都在上升。原发性肠系膜NETs极为罕见。起源于肠系膜的实体瘤通常是转移性的。我们报告一例极为罕见的回肠系膜原发性2级NET（NET G2）病例。
一名54岁男性因先前诊断的右肠系膜肿瘤被转诊至我院进一步检查。腹部右侧有轻度压痛，但未触及肿块。氟脱氧葡萄糖正电子发射断层扫描（FDG-PET）显示右腹部有轻微的FDG摄取（最大标准化摄取值为2.0），怀疑为良性或低级别恶性肿瘤。我们通过回肠切除术（90cm）切除了回肠系膜肿瘤。肿瘤大小为55×33×33mm，切面呈淡黄色白色。免疫组织化学显示突触素和嗜铬粒蛋白A弥漫性染色，CD56局灶性染色。Ki-67指数为3%。最终病理诊断为NET G2。患者术后恢复顺利，术后1.5年未复发。由于组织学诊断为NET G2，且确定肿瘤可通过手术完全切除，因此该患者未进行术后抗肿瘤治疗。
我们报告了一例极为罕见的原发性回肠系膜NET病例。在FDG-PET检查中显示轻微FDG摄取的肠系膜肿瘤应考虑为高分化NET。
