升结肠癌跳跃式转移至右颈部及左腋下淋巴结1例分析

Metastasis from Cancer of the Ascending Colon in the Right Cervical and Left Axillary Cavity Lymph Nodes

升结肠癌跳跃式转移至右颈部及左腋下淋巴结比较少见,其原因可能与淋巴结免疫反应、"土壤学说"等有关,提示临床工作中应对来源不明的颈部及腋下淋巴结转移癌进行全面检查以排除消化道原发肿瘤的可能。原发灶不明的颈部淋巴结转移癌行PET-CT检查可发现30%～40%的原发灶,因其大多来源于头颈部肿瘤,行大野根治性放疗可取得较好的疗效。为明确颈部淋巴结转移灶来源于结肠癌除影像学检查外应进行免疫组织化学检查,以免造成漏诊或误诊。如无出血、梗阻或穿孔等急症,Ⅳ期结肠癌手术治疗不被推荐,应采用全身化疗,且全身化疗可以取得较好疗效。结肠癌容易被误诊为急性阑尾炎,除了个别病例临床表现相近外,往往是由于鉴别诊断不够充分,缺乏必要的辅助检查,临床工作中应尽量避免此类误诊的发生。

Metastases from cancer of the ascending colon to the right cervical and left axillary cavity lymph nodes is rare. The immune reaction of lymph nodes is one of the most likely explanations for this pattern of metastasis. Some may interpret this phenomenon as an example of the ＂seed and soil＂ hypothesis. PET-CT scan can detect 30-40% of unknown primary tumors with cervical lymph node metastases, while some domestic institutes report that the proportion should be higher because PET-CT scan was performed without previous routine examination. Because most of the metastases are from tumors of the head or the cervix, large field radical radiotherapy will achieve a better outcome. In our routine clinical work, a systemic examination of the alimentary tract should be performed for patients with unknown primary tumors. To verify cervical lymph node metastases are truly arising from cancer of the ascending colon, immunohistochemistry is recommended in addition to routine imaging. Expression of CDX2, an alimentary tract-specific immunohistochemical marker, should be assessed along with markers for lung cancer. For patients without emergencies such as obstruction, bleeding or perforation, stage Ⅳ colon cancer should not be treated with surgery because of the risk for dissemination and an expected favorable response to systemic chemotherapy. The chemotherapy for colorectal cancer has been standardized, and the suggested regimen includes only three kinds of medicine： cisplatin, 5-FU, and Erie topotecan. Any combination of these 3 drugs should produce a rather good clinical outcome. Ascending colon cancer can be easily misdiagnosed as acute appendix inflammation due to insufficient differential diagnosis or lack of necessary supplementary examinations.