Rectal Carcinoid of Less Than 2cm in Diameter with sm Invasion Associating with Lymph Node Metastasis -Report of Two Cases-

Yasuhiko Nagano, Hideyuki Ike, Shigeharu Komatsu, Seiichiro Iwata,
Hirosi Ando, Katsumi Go, Masazumi Takahasi, Akira Sugita,
Shigeo Ohki and Hirosi Shimada

Second Department of Surgery, Yokohama City University School of Medicine

In case 1, a 42-year-old female had a Isp type polyp of the lower rectum with a 1.0cm in diameter. We conducted endoscopic polypectomy, and histological examination revealed carcinoid tumor, sm invasion, positive for the stump and for vascular invasion. Therefore, low anterior resection of the rectum was performed. A metastatic pararectal lymph node was diagnosed by frozen section analysis. In case 2, a 61-year-old man had a Isp type carcinoid of the lower rectum with a 0.8cm diameter. We conducted endoscopic polypectomy, and histological examination showed sm invasion, and positive findings for stump and for vascular invasion. Therefore, low anterior resection of the rectum was performed, and histological examination of the resected specimen revealed a metastatic pararectal lymph node. Carcinoids of the rectum with a diameter of less than 2cm and submucosal layer invasion associated with lymph node metastasis is rare. Only 18 cases, including the present two cases, have been reported in the Japanese literature. Of these, 91.7% were positive for vascular invasion, therefore, this finding appeares to be a useful predictor of lymph node involvement. Endoscopic polypectomy is indicated for rectal carcinoids which are less than 5mm in diameter, and local excision is indicated for lesions more than 5mm in diameter. Furthermore, under histological examination, radical operation with lymph node dissection is indicated for cases that are positive for vascular invasion and invasion deapth of more than sm2.

Key words
rectal carcinoid, lymph node metastasis of rectal carcinoid

Reprint requests
Yasuhiko Nagano Second Department of Surgery, Yokohama City University School of Medicine Urafune Hospital 3-46 Urafune-cho, Minami-ku, Yokohama, 232-0024 JAPAN

Accepted
February 24, 1999

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