Nishiura Bunpei, Kumamoto Kensuke, Akamoto Shintaro, Asano Eisuke, Ando Yasuhisa, Suto Hironobu, Kishino Takayoshi, Oshima Minoru, Fujiwara Masao, Usuki Hisashi, Okano Keiichi, Suzuki Yasuyuki
Department of Gastroenterological Surgery, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan.
Department of Surgery, Sumitomo Besshi Hospital, Niihama, Japan.
Surg Case Rep. 2020 May 11;6(1):100. doi: 10.1186/s40792-020-00858-1.
The observation of spontaneous regression (SR) has been well documented for many cancer types, including renal cell carcinoma, non-Hodgkin's lymphoma, leukemia, neuroblastoma, and malignant melanoma. However, the SR frequency in colorectal cancer is very rare. Therefore, the accumulation of SR colorectal cancer cases might contribute to find the regression mechanism.
A 67-year-old woman received colonoscopy due to being positive for fecal occult blood testing and was diagnosed as having a transverse colon cancer at a local hospital. She was admitted to our institution for surgical treatment of the colon cancer. The colonoscopy revealed a type 2 tumor of 13 mm in diameter at the hepatic flexure of the transverse colon. The enhanced computed tomography (CT) showed an enlarged lymph node in the intermediate lymph node region. The 18F-fluorodeoxyglucose positron emission tomography/CT showed no abnormal accumulation on the transverse colon; however, an abnormal accumulation was found at the enlarged lymph node. The patient was preoperatively diagnosed as having advanced transverse colon cancer with lymph node metastasis and underwent laparoscopic right hemicolectomy with D3 lymph node dissection. Pathological examination showed only a scar-like tissue and no cancerous lesion in the transverse colon, while a metastatic lymph node was histologically confirmed in the intermediate lymph node region. Loss of MLH1 and PMS2 expression was observed in the cancer cells of both biopsy specimens and resected lymph nodes. No recurrence was seen for 5 years after surgery.
We reported a rare case of SR of the primary transverse colon cancer without regression of the metastatic regional lymph node. We considered that colorectal cancer with SR should be resected because even if SR of the primary lesion occurs, lymph node metastasis might have an inconsistent behavior as shown in the present case.
许多癌症类型都有自发消退（SR）的观察记录，包括肾细胞癌、非霍奇金淋巴瘤、白血病、神经母细胞瘤和恶性黑色素瘤。然而，结直肠癌的SR发生率非常低。因此，积累SR结直肠癌病例可能有助于找到消退机制。
一名67岁女性因粪便潜血试验呈阳性接受结肠镜检查，在当地医院被诊断为横结肠癌。她因结肠癌手术治疗入住我院。结肠镜检查显示横结肠肝曲处有一个直径13毫米的2型肿瘤。增强计算机断层扫描（CT）显示中间淋巴结区域有一个肿大的淋巴结。18F-氟脱氧葡萄糖正电子发射断层扫描/CT显示横结肠无异常聚集；然而，在肿大的淋巴结处发现了异常聚集。患者术前被诊断为晚期横结肠癌伴淋巴结转移，接受了腹腔镜右半结肠切除术及D3淋巴结清扫术。病理检查显示横结肠仅为瘢痕样组织，无癌性病变，而中间淋巴结区域经组织学证实有转移性淋巴结。活检标本和切除淋巴结的癌细胞中均观察到MLH1和PMS2表达缺失。术后5年未见复发。
我们报告了一例罕见的原发性横结肠癌自发消退但转移性区域淋巴结未消退的病例。我们认为，即使原发性病变出现自发消退，结直肠癌伴自发消退也应切除，因为如本病例所示，淋巴结转移可能有不一致的表现。
