Arakawa Yusuke, Miyake Hidenori, Horiguchi Hidehisa, Inokuchi Taku, Hino Naoki, Ogasawara Takashi, Kuroda Takeshi, Yamasaki Shinichi
Department of Surgery, Tokushima Municipal Hospital, Kitajyosanjima 2-34, Tokushima, 770-0812, Japan.
Department of Pathology, Tokushima Municipal Hospital, Kitajyosanjima 2-34, Tokushima, 770-0812, Japan.
Surg Case Rep. 2018 Aug 30;4(1):106. doi: 10.1186/s40792-018-0508-2.
Solitary fibrous tumor (SFT) is a prototypical mesenchymal neoplasm that induces non-islet cell tumor hypoglycemia (NICTH) due to overproduction of insulin-like growth factor 2 (IGF2). We here report the case of a malignant SFT associated with a hypoglycemia attack.
An 81-year-old man with a large subphrenic mass presented with hypoglycemia and loss of consciousness. His serum insulin and IGF1 levels were relatively low, suggesting an excessively high serum IGF2 levels. Preoperative Western blotting of serum confirmed the overproduction of high-molecular-weight IGF2. After total tumor resection, the patient recovered from hypoglycemia without the need for further treatment. Histological examination revealed proliferation of spindle cells and frequent nuclear mitoses with STAT6 and CD34 immunoreactivity, which led to the diagnosis of malignant SFT. IGF2 was strongly upregulated in the tumor upon immunohistochemistry, consistent with the report of NICTH. In addition, the tumor expressed IGF2 receptor (IGF2R) but not IGF1R.
The present results indicate that the tumor co-expressed IGF2 and IGF2R. IGF2R has not previously been recognized as a tyrosine kinase receptor participating in cell signal transduction. Thus, further case series are required to determine whether IGF2R overexpression reflects the action of an unknown autocrine/paracrine system involving IGF2 for cell proliferation or for the scavenging and degradation of IGF2.
孤立性纤维瘤（SFT）是一种典型的间叶性肿瘤，可因胰岛素样生长因子2（IGF2）过度产生而导致非胰岛细胞瘤性低血糖症（NICTH）。我们在此报告一例与低血糖发作相关的恶性SFT病例。
一名81岁男性，患有巨大膈下肿物，出现低血糖和意识丧失。其血清胰岛素和IGF1水平相对较低，提示血清IGF2水平过高。术前血清免疫印迹法证实高分子量IGF2过度产生。肿瘤全切术后，患者低血糖症状缓解，无需进一步治疗。组织学检查显示梭形细胞增生，核分裂象常见，STAT6和CD34免疫反应阳性，诊断为恶性SFT。免疫组化显示肿瘤中IGF2强烈上调，与NICTH报道一致。此外，肿瘤表达IGF2受体（IGF2R）但不表达IGF1R。
目前结果表明肿瘤同时表达IGF2和IGF2R。IGF2R以前未被认为是参与细胞信号转导的酪氨酸激酶受体。因此，需要更多病例系列研究来确定IGF2R过表达是否反映了一种未知的自分泌/旁分泌系统的作用，该系统涉及IGF2促进细胞增殖或清除及降解IGF2。
